{"id":757752,"date":"2026-06-24T09:08:16","date_gmt":"2026-06-24T09:08:16","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/757752\/"},"modified":"2026-06-24T09:08:16","modified_gmt":"2026-06-24T09:08:16","slug":"inertial-migration-of-spherical-particle-in-shear-flow-of-shear-thinning-fluids-journal-of-fluid-mechanics","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/757752\/","title":{"rendered":"Inertial migration of spherical particle in shear flow of shear-thinning fluids | Journal of Fluid Mechanics"},"content":{"rendered":"<p>3.1. Effect of Carreau number, viscosity ratio and power-law index<\/p>\n<p class=\"p\"> We begin by examining the influence of shear thinning on the lateral migration of a neutrally buoyant spherical particle in plane Couette flow, with a fixed confinement ratio of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline257.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline257.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p> (which is maintained throughout this section unless otherwise specified). The extent of shear thinning is characterised by the Carreau number (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline258.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline258.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>), which represents the relative importance of the shear rate to the intrinsic time scale of the fluid; larger values of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline259.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline259.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> correspond to stronger shear-thinning effects. The viscosity ratio (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline260.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline260.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p>) quantifies the contrast between the infinite-shear and zero-shear viscosities, thereby controlling the strength of viscosity variation between regions of high and low shear rate. The power-law index (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline261.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline261.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>) governs the degree of shear thinning in the intermediate shear-rate regime, with smaller values of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline262.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline262.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> corresponding to more pronounced shear-thinning behaviour. We first examine the effect of the Carreau number by analysing the bifurcation behaviour of the equilibrium particle position. <a class=\"xref fig\" href=\"#f3\">Figure\u00a03<\/a>(a) presents the regime diagram in the <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline263.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"70\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline263.png\" data-zoomable=\"false\" alt=\"left parenthesis italic Re Subscript c Baseline comma upper C u right parenthesis\"\/><\/p>\n<p>$({\\textit{Re}}_c, Cu)$<\/p>\n<p> parameter space for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline264.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline264.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline265.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline265.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. The solid demarcating line represents the critical condition separating two distinct migration regimes. For a fixed Carreau number, this boundary corresponds to a critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline266.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline266.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>; conversely, for a fixed Reynolds number, it defines a critical Carreau number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline267.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline267.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p>. Below this boundary (i.e. <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline268.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline268.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline less than italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_c \\lt {\\textit{Re}}_{{cr}}$<\/p>\n<p> for fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline269.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline269.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, or <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline270.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline270.png\" data-zoomable=\"false\" alt=\"upper C u less than upper C u Subscript c r\"\/><\/p>\n<p>$Cu \\lt Cu_{{cr}}$<\/p>\n<p> for fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline271.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline271.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>), the particle ultimately migrates to the channel centreline irrespective of its initial release position. In contrast, beyond the critical condition (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline272.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline272.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline greater than italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_c \\gt {\\textit{Re}}_{{cr}}$<\/p>\n<p> or <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline273.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline273.png\" data-zoomable=\"false\" alt=\"upper C u greater than upper C u Subscript c r\"\/><\/p>\n<p>$Cu \\gt Cu_{{cr}}$<\/p>\n<p>), the centreline becomes unstable and the particle migrates towards an off-centre equilibrium position. The final equilibrium location depends on the initial release position. If the particle is released between the centreline and the lower half of the channel, it migrates to a stable off-centre position within that region. Similarly, if released between the centreline and the upper wall, it approaches a symmetric off-centre equilibrium in the upper half of the channel. Thus, the bifurcation is supercritical in nature: once the critical threshold (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline274.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline274.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> for fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline275.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline275.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> or <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline276.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline276.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p> for fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline277.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline277.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>) is exceeded, the centreline loses stability and symmetric off-centre equilibria emerge. Further insight into the nature of the bifurcation is obtained by examining the dependence of the equilibrium position on the Carreau number. <a class=\"xref fig\" href=\"#f3\">Figure\u00a03<\/a>(b) shows the equilibrium position <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline278.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"50\" height=\"18\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline278.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H$<\/p>\n<p> as a function of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline279.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline279.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> for a fixed channel Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline280.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline280.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 100\"\/><\/p>\n<p>${\\textit{Re}}_c = 100$<\/p>\n<p>, with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline281.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline281.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline282.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline282.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. This analysis is aimed at characterising the scaling behaviour of particle migration in a shear-thinning fluid near the onset of instability. For sufficiently small <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline283.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline283.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, the steady equilibrium remains at the channel centreline (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline284.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"93\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline284.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H equals 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H = 0.5$<\/p>\n<p>), indicating stability of the symmetric state. Beyond a threshold value of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline285.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline285.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, the centreline loses stability and the particle migrates to an off-centre equilibrium position (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline286.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"94\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline286.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H not equals 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H \\neq 0.5$<\/p>\n<p>), with the direction determined by the initial release location. Furthermore, increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline287.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline287.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> drives the particle progressively farther from the centreline and closer to the wall, reflecting the strengthening influence of shear-thinning effects. The value of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline288.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline288.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> at which the transition from centreline to off-centre equilibrium occurs is defined as the critical Carreau number, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline289.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline289.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p>. For the present parameter set, the transition is observed between <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline290.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"51\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline290.png\" data-zoomable=\"false\" alt=\"upper C u equals 1\"\/><\/p>\n<p>$Cu = 1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline291.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"52\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline291.png\" data-zoomable=\"false\" alt=\"upper C u equals 2\"\/><\/p>\n<p>$Cu = 2$<\/p>\n<p>, yielding an estimate <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline292.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"80\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline292.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r Baseline almost equals 1.2\"\/><\/p>\n<p>$Cu_{{cr}} \\approx 1.2$<\/p>\n<p>. This estimate is obtained from simulations performed with refined parameter sampling in this interval (using increments of Carreau number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline293.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"79\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline293.png\" data-zoomable=\"false\" alt=\"normal upper Delta upper C u equals 0.1\"\/><\/p>\n<p>$\\Delta Cu = 0.1$<\/p>\n<p>) near the bifurcation point. In general, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline294.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline294.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p> depends on <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline295.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline295.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline296.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline296.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline297.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline297.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline298.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline298.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p>; for example, <a class=\"xref fig\" href=\"#f3\">figure\u00a03<\/a>(a) shows that <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline299.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline299.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p> varies with the channel Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline300.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline300.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>. In the present discussion, however, we restrict attention to this representative case. For <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline301.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline301.png\" data-zoomable=\"false\" alt=\"upper C u less than upper C u Subscript c r\"\/><\/p>\n<p>$Cu \\lt Cu_{{cr}}$<\/p>\n<p>, the particle migrates to the centreline irrespective of its initial position, whereas for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline302.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline302.png\" data-zoomable=\"false\" alt=\"upper C u greater than upper C u Subscript c r\"\/><\/p>\n<p>$Cu \\gt Cu_{{cr}}$<\/p>\n<p>, symmetric off-centre equilibria emerge and the final state depends on the initial condition. The inset of <a class=\"xref fig\" href=\"#f3\">figure\u00a03<\/a>(b) highlights the near-critical behaviour using the reduced control parameter <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline303.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"168\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline303.png\" data-zoomable=\"false\" alt=\"delta equals left parenthesis upper C u minus upper C u Subscript c r Baseline right parenthesis divided by upper C u Subscript c r\"\/><\/p>\n<p>$\\delta = (Cu &#8211; Cu_{{cr}})\/Cu_{{cr}}$<\/p>\n<p>, with the vertical axis plotted as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline304.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"93\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline304.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H minus 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H &#8211; 0.5$<\/p>\n<p>. The observed square-root variation of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline305.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"8\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline305.png\" data-zoomable=\"false\" alt=\"delta\"\/><\/p>\n<p>$\\delta$<\/p>\n<p> with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline306.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"93\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline306.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H minus 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H &#8211; 0.5$<\/p>\n<p> near onset is consistent with the canonical scaling of a supercritical pitchfork bifurcation. Additional insight is obtained by examining the variation of the equilibrium position with the channel Reynolds number. <a class=\"xref fig\" href=\"#f3\">Figure\u00a03<\/a>(c) shows the steady-state equilibrium position <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline307.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"50\" height=\"18\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline307.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H$<\/p>\n<p> as a function of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline308.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline308.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> for several values of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline309.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline309.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline310.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline310.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline311.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline311.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p>. For each fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline312.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline312.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, the particle remains at the channel centreline (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline313.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"93\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline313.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H equals 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H = 0.5$<\/p>\n<p>) up to a critical Reynolds number, beyond which it migrates to an off-centre equilibrium position, thereby forming a bifurcation diagram in <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline314.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline314.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>. The Reynolds number at which this transition occurs is defined as the critical Reynolds number, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline315.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline315.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>. For example, in the Newtonian limit (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline316.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"52\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline316.png\" data-zoomable=\"false\" alt=\"upper C u equals 0\"\/><\/p>\n<p>$Cu = 0$<\/p>\n<p>) and for the present confinement ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline317.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline317.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>, the critical value is approximately <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline318.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"79\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline318.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r Baseline almost equals 153\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}} \\approx 153$<\/p>\n<p>. For <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline319.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"78\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline319.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline greater than italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_c \\gt {\\textit{Re}}_{{cr}}$<\/p>\n<p>, the particle migrates away from the centreline and settles at an off-centre equilibrium position (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline320.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"94\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline320.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H not equals 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H \\neq 0.5$<\/p>\n<p>). As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline321.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline321.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases, this critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline322.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline322.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> decreases monotonically, indicating that shear-thinning effects reduce the inertial threshold required to destabilise the centreline equilibrium. Consistent with the trends observed earlier, for a fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline323.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline323.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>, larger values of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline324.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline324.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> also shift the off-centre equilibrium progressively closer to the channel wall.<\/p>\n<p>Figure 3.<\/p>\n<p class=\"p\">(a) Regime diagram in the <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline234.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline234.png\" data-zoomable=\"false\" alt=\"left parenthesis italic Re Subscript c Baseline comma upper C u right parenthesis\"\/><\/p>\n<p>$({\\textit{Re}}_c,\\,Cu)$<\/p>\n<p> parameter space for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline235.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline235.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline236.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline236.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline237.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline237.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. The solid line represents the critical Reynolds number, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline238.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline238.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>, separating two distinct migration regimes. For <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline239.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline239.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> values to the right of the boundary, the particle migrates to an off-centre equilibrium position, whereas for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline240.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline240.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> values to the left of the boundary, the particle returns to the channel centreline. (b) Normalised equilibrium position of the particle, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline241.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"50\" height=\"18\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline241.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H$<\/p>\n<p>, as a function of the Carreau number, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline242.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline242.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>. The results exhibit a supercritical pitchfork bifurcation, in which the particle migrates from the channel centreline to off-centre equilibrium positions as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline243.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline243.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> exceeds the critical value, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline244.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline244.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p>. Note that this <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline245.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"34\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline245.png\" data-zoomable=\"false\" alt=\"upper C u Subscript c r\"\/><\/p>\n<p>$Cu_{{cr}}$<\/p>\n<p> is a function of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline246.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline246.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>. Here, the bifurcation shown corresponds to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline247.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"73\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline247.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 100\"\/><\/p>\n<p>${\\textit{Re}}_c = 100$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline248.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline248.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline249.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline249.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline250.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline250.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. Inset: variation of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline251.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"93\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline251.png\" data-zoomable=\"false\" alt=\"upper Z Subscript italic eq Baseline divided by upper H minus 0.5\"\/><\/p>\n<p>$Z_{{\\textit{eq}}}\/H &#8211; 0.5$<\/p>\n<p> with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline252.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"168\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline252.png\" data-zoomable=\"false\" alt=\"delta equals left parenthesis upper C u minus upper C u Subscript c r Baseline right parenthesis divided by upper C u Subscript c r\"\/><\/p>\n<p>$\\delta = (Cu &#8211; Cu_{{cr}})\/Cu_{{cr}}$<\/p>\n<p> near the bifurcation point, showing square-root scaling close to onset. (c) Normalised equilibrium position across the channel as a function of the channel Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline253.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline253.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> for different Carreau numbers, with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline254.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline254.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline255.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline255.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline256.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline256.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig3.png\" class=\"aop-lazy-load-image\" width=\"3769\" height=\"2674\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig3.png\" data-zoomable=\"true\" alt=\"Three graphs depict particle migration in non-Newtonian fluids.\"\/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig4.png\" class=\"aop-lazy-load-image\" width=\"3909\" height=\"1354\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig4.png\" data-zoomable=\"true\" alt=\"Two line graphs depict the variation of critical Reynolds number with Carreau number for different parameters.\"\/><\/p>\n<p class=\"p\"> Having established the influence of the Carreau number on the critical Reynolds number, we now examine how the remaining rheological parameters such as viscosity ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline335.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline335.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> and power-law index <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline336.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline336.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> affect the onset of lateral migration. The dependence of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline337.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline337.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> on <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline338.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline338.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> for different viscosity ratios is shown in <a class=\"xref fig\" href=\"#f4\">figure\u00a04<\/a>(a) for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline339.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"55\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline339.png\" data-zoomable=\"false\" alt=\"beta equals 0.9\"\/><\/p>\n<p>$\\beta = 0.9$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline340.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"22\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline340.png\" data-zoomable=\"false\" alt=\"0.5\"\/><\/p>\n<p>$0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline341.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"22\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline341.png\" data-zoomable=\"false\" alt=\"0.1\"\/><\/p>\n<p>$0.1$<\/p>\n<p>, with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline342.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline342.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. In each case, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline343.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline343.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> is determined from simulations performed with unit increments of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline344.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline344.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> near the transition point. For all viscosity ratios, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline345.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline345.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> decreases monotonically with increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline346.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline346.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>. Moreover, the reduction becomes more pronounced as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline347.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline347.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> decreases, corresponding to a larger viscosity contrast between low- and high-shear regions and therefore stronger shear-thinning effects. We next consider the role of the power-law index <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline348.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline348.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>. <a class=\"xref fig\" href=\"#f4\">Figure\u00a04<\/a>(b) shows the variation of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline349.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline349.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline350.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline350.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline351.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline351.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline352.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"22\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline352.png\" data-zoomable=\"false\" alt=\"0.5\"\/><\/p>\n<p>$0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline353.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"30\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline353.png\" data-zoomable=\"false\" alt=\"0.75\"\/><\/p>\n<p>$0.75$<\/p>\n<p>, at a fixed viscosity ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline354.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline354.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p>. The results indicate that <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline355.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline355.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> decreases as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline356.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline356.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> decreases, with the sensitivity becoming increasingly significant at lower values of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline357.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline357.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>. Since smaller <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline358.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline358.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> corresponds to stronger shear-thinning behaviour, this trend is consistent with the variations observed with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline359.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline359.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline360.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline360.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p>. Taken together, these results demonstrate that enhanced shear thinning, whether achieved by increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline361.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline361.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, decreasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline362.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline362.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> or reducing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline363.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline363.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>, lowers the critical Reynolds number required to destabilise the centreline equilibrium and promotes particle migration at weaker inertial forcing.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig5.png\" class=\"aop-lazy-load-image\" width=\"3881\" height=\"2785\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig5.png\" data-zoomable=\"true\" alt=\"Three line graphs depict the variation of dimensionless lift force on a neutrally buoyant sphere in confined Couette flow.\"\/><\/p>\n<p class=\"p\"> To further understand the bifurcation behaviour described above, we examine the stability of both the centreline and off-centre equilibrium positions by analysing the lateral force acting on the particle. Specifically, we compute the non-dimensional lift force as a function of the particle\u2019s lateral position across the channel height, as shown in <a class=\"xref fig\" href=\"#f5\">figure\u00a05<\/a>(a\u2013c). The lift force is evaluated by placing the particle at various <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline378.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"8\" height=\"10\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline378.png\" data-zoomable=\"false\" alt=\"z\"\/><\/p>\n<p>$z$<\/p>\n<p>-locations while allowing free translation and rotation in all directions except <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline379.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"8\" height=\"10\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline379.png\" data-zoomable=\"false\" alt=\"z\"\/><\/p>\n<p>$z$<\/p>\n<p>, where translation is constrained. The resulting lift force is normalised using <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline380.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"120\" height=\"20\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline380.png\" data-zoomable=\"false\" alt=\"upper F Subscript s Baseline equals rho upper V Subscript w Superscript 2 Baseline a Superscript 4 Baseline divided by upper H squared\"\/><\/p>\n<p>$F_s = \\rho V_w^2 a^4 \/ H^2$<\/p>\n<p> (Ho\u00a0&amp; Leal <a class=\"xref bibr\" href=\"#ref26\">Reference Ho and Leal1974<\/a>), allowing direct comparison across different flow conditions and rheological parameters. <a class=\"xref fig\" href=\"#f5\">Figure\u00a05<\/a> presents the lift-force profiles for variations in the Carreau number (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline381.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline381.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>), viscosity ratio (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline382.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline382.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p>) and power-law index (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline383.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline383.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>), with all other parameters held constant. <a class=\"xref fig\" href=\"#f5\">Figure\u00a05<\/a>(a) illustrates the effect of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline384.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline384.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline385.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline385.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline386.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline386.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline387.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline387.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. For a Newtonian fluid (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline388.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"52\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline388.png\" data-zoomable=\"false\" alt=\"upper C u equals 0\"\/><\/p>\n<p>$Cu = 0$<\/p>\n<p>), the lift-force profile exhibits a single zero crossing at the channel centreline, with a negative slope, indicating that the centreline is a stable equilibrium. As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline389.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline389.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases, reflecting stronger shear-thinning effects, two additional off-centre zero crossings emerge. These off-centre crossings have negative slopes, identifying them as stable equilibrium positions, while the slope at the centreline becomes positive, signalling the loss of its stability. This transition indicates that stronger shear thinning promotes off-centre migration, even when the particle initially resides at the centreline. <a class=\"xref fig\" href=\"#f5\">Figure\u00a05<\/a>(b) explores the role of the viscosity ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline390.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline390.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline391.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline391.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline392.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline392.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline393.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline393.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. For higher <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline394.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline394.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> values (closer to unity), the lift-force profiles resemble those of Newtonian fluids, with a single stable equilibrium at the centreline. Reducing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline395.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline395.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p>, which increases the contrast between zero and infinite shear viscosities, destabilises the centreline and promotes the appearance of off-centre stable equilibria. This demonstrates that the distribution of shear-dependent viscosity across the channel can significantly influence particle migration, with stronger viscosity contrasts favouring lateral displacement from the centre. <a class=\"xref fig\" href=\"#f5\">Figure\u00a05<\/a>(c) highlights the influence of the power-law index <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline396.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline396.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline397.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline397.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline398.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline398.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline399.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline399.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline400.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline400.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> decreases, corresponding to stronger shear-thinning behaviour, the centreline equilibrium is progressively destabilised, and stable off-centre equilibria emerge. This shows that it is not only the magnitude of shear thinning (via <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline401.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline401.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>), but that also the intrinsic rheological character of the fluid (via <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline402.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline402.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline403.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline403.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>) critically governs the equilibrium positions of the particle. Collectively, these results reveal a consistent and unified trend: increasing the intensity of shear thinning, whether by increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline404.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline404.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, decreasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline405.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline405.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> or reducing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline406.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline406.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>, leads to an earlier onset of lateral migration and the formation of stable off-centre equilibrium positions. By systematically varying one parameter at a time, the lift-force profiles provide a clear and quantitative picture of how shear thinning modulates particle stability, highlighting the intricate interplay between fluid rheology and inertial effects in confined flows. To place these findings in context, it is useful to compare them with Newtonian fluids. Previous studies have shown that the lift force decreases with increasing Reynolds number, a phenomenon attributed to inertial screening (Fox, Schneider\u00a0&amp; Khair <a class=\"xref bibr\" href=\"#ref24\">Reference Fox, Schneider and Khair2021<\/a>). As Reynolds number increases, the disturbance flow induced by the particle becomes increasingly confined to its vicinity, thereby reducing hydrodynamic interactions with the channel walls and leading to a weaker lift force. In shear-thinning fluids at fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline407.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline407.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>, we observe a qualitatively similar reduction in lift force on increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline408.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline408.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, decreasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline409.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline409.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> or reducing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline410.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline410.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> (see <a class=\"xref fig\" href=\"#f5\">figure\u00a05<\/a><br \/>\na\u2013c), although the underlying mechanism is different. Here, the shear-thinning rheology reduces the viscosity in regions of high shear rate near the particle surface, thereby diminishing local viscous stresses. This rheological effect confines the disturbance flow more closely to the particle, effectively screening particle\u2013wall interactions which in turn reduces the overall lift force. These insights emphasise that even subtle changes in the fluid\u2019s shear-rate-dependent properties can markedly alter the behaviour of suspended particles, offering a predictive framework for understanding particle migration in complex fluids.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig6.png\" class=\"aop-lazy-load-image\" width=\"3830\" height=\"2156\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig6.png\" data-zoomable=\"true\" alt=\"Heat maps showing dimensionless viscosity contours in plane Couette flow for different Carreau numbers.\"\/><\/p>\n<p class=\"p\"> Next, to examine the reduction in the critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline419.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline419.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> with increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline420.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline420.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> and decreasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline421.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline421.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline422.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline422.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p>, kinematic viscosity <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline423.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"49\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline423.png\" data-zoomable=\"false\" alt=\"nu left parenthesis x comma z right parenthesis\"\/><\/p>\n<p>$\\nu (x,z)$<\/p>\n<p> contours are plotted, where the viscosity is normalised by the zero-shear-rate viscosity <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline424.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"14\" height=\"11\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline424.png\" data-zoomable=\"false\" alt=\"nu 0\"\/><\/p>\n<p>$\\nu _{0}$<\/p>\n<p>. <a class=\"xref fig\" href=\"#f6\">Figure\u00a06<\/a>(a\u2013d) presents steady-state viscosity contours for increasing Carreau numbers, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline425.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"117\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline425.png\" data-zoomable=\"false\" alt=\"upper C u equals 0.1 comma 1 comma 10\"\/><\/p>\n<p>$Cu = 0.1,\\, 1,\\, 10$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline426.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"25\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline426.png\" data-zoomable=\"false\" alt=\"100\"\/><\/p>\n<p>$100$<\/p>\n<p>, at fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline427.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline427.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline428.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline428.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline429.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline429.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. These contours illustrate how varying <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline430.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline430.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> affects the local viscosity field around the particle and, consequently, its equilibrium. At low Carreau number (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline431.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline431.png\" data-zoomable=\"false\" alt=\"upper C u equals 0.1\"\/><\/p>\n<p>$Cu = 0.1$<\/p>\n<p>, <a class=\"xref fig\" href=\"#f6\">figure\u00a06<\/a><br \/>\na), the fluid exhibits very weak shear thinning, resulting in a nearly uniform viscosity field across the channel. In this regime, viscosity is only slightly reduced in the vicinity of the particle due to localised shear. Consequently, the particle remains near the channel centreline, as the weak and nearly symmetric viscosity gradients generate negligible lift asymmetry. As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline432.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline432.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases (<a class=\"xref fig\" href=\"#f6\">figure\u00a06<\/a><br \/>\nb\u2013d), the shear-thinning response becomes progressively stronger, leading to a pronounced reduction in viscosity near the particle surface, where local velocity gradients are largest. This reduction in viscosity locally around the particle modifies the local stress distribution which eventually destabilises the centreline equilibrium, causing the particle to migrate towards an off-centre equilibrium position, the exact location of which depends on the initial particle position. The destabilisation of the centreline can be rationalised through the Carreau constitutive relation: larger local velocity gradients induce a stronger reduction in viscosity near the particle surface, which decreases the local viscous force. This reduction effectively makes local inertial force stronger than the viscous force, thereby accelerating the onset of inertial migration away from the centreline. At low <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline433.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline433.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, where the fluid behaviour is nearly Newtonian, the centreline remains a stable equilibrium. However, as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline434.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline434.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases, the enhanced shear thinning generates progressively stronger viscosity gradients, which in turn promote off-centre migration. This mechanism is reflected quantitatively in the critical Reynolds number, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline435.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline435.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>, for lateral migration. For instance, at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline436.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"55\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline436.png\" data-zoomable=\"false\" alt=\"beta equals 0.9\"\/><\/p>\n<p>$\\beta = 0.9$<\/p>\n<p> (<a class=\"xref fig\" href=\"#f4\">figure\u00a04<\/a><br \/>\na), the Newtonian limit (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline437.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"58\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline437.png\" data-zoomable=\"false\" alt=\"upper C u right arrow 0\"\/><\/p>\n<p>$Cu \\to 0$<\/p>\n<p>) yields <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline438.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"79\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline438.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r Baseline almost equals 153\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}} \\approx 153$<\/p>\n<p>, whereas at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline439.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline439.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline440.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline440.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> decreases markedly to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline441.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"72\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline441.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r Baseline almost equals 96\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}\\approx 96$<\/p>\n<p>. This reduction demonstrates that local shear thinning lowers the effective viscous resistance, facilitating an earlier onset of off-centre equilibrium positions as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline442.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline442.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases. Overall, the viscosity contours provide a clear visualisation of how shear thinning modulates the local stress field around the particle, thereby governing its migration behaviour in confined flows.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig7.png\" class=\"aop-lazy-load-image\" width=\"3866\" height=\"2128\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig7.png\" data-zoomable=\"true\" alt=\"Heat map showing Reynolds number contours around a particle in a fluid flow.\"\/><\/p>\n<p class=\"p\"> To rationalise this migration using the local Reynolds number distribution, we quantify the spatial variation of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline454.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"50\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline454.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l Baseline left parenthesis bold italic x right parenthesis\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }(\\boldsymbol{x})$<\/p>\n<p>, following Lashgari et\u00a0al. (<a class=\"xref bibr\" href=\"#ref36\">Reference Lashgari, Picano, Breugem and Brandt2012<\/a>) and Patel, Rothstein\u00a0&amp; Modarres-Sadeghi (<a class=\"xref bibr\" href=\"#ref55\">Reference Patel, Rothstein and Modarres-Sadeghi2022<\/a>), in the mid-plane (i.e. <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline455.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"18\" height=\"10\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline455.png\" data-zoomable=\"false\" alt=\"x z\"\/><\/p>\n<p>$xz$<\/p>\n<p>-plane) passing through the particle centre. The local Reynolds number is defined as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline456.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"167\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline456.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l Baseline left parenthesis bold italic x right parenthesis equals upper V Subscript w Baseline upper H divided by nu left parenthesis x comma z right parenthesis\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }(\\boldsymbol{x}) = V_w H \/ \\nu (x,z)$<\/p>\n<p>, which provides a local measure of the balance between inertial and viscous stresses and can therefore be interpreted as an effective local Reynolds number. Contours of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline457.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"50\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline457.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l Baseline left parenthesis bold italic x right parenthesis\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }(\\boldsymbol{x})$<\/p>\n<p> at steady state for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline458.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline458.png\" data-zoomable=\"false\" alt=\"upper C u equals 0.1\"\/><\/p>\n<p>$Cu = 0.1$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline459.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"7\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline459.png\" data-zoomable=\"false\" alt=\"1\"\/><\/p>\n<p>$1$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline460.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"16\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline460.png\" data-zoomable=\"false\" alt=\"10\"\/><\/p>\n<p>$10$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline461.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"25\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline461.png\" data-zoomable=\"false\" alt=\"100\"\/><\/p>\n<p>$100$<\/p>\n<p> are shown in <a class=\"xref fig\" href=\"#f7\">figure\u00a07<\/a>(a\u2013d) for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline462.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline462.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline463.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline463.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline464.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline464.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. As the Carreau number increases from <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline465.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline465.png\" data-zoomable=\"false\" alt=\"upper C u equals 0.1\"\/><\/p>\n<p>$Cu = 0.1$<\/p>\n<p> to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline466.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"25\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline466.png\" data-zoomable=\"false\" alt=\"100\"\/><\/p>\n<p>$100$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline467.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline467.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }$<\/p>\n<p> increases both around the particle surface and in the bulk region far away from the particle. Away from the particle, the distribution of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline468.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline468.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }$<\/p>\n<p> is nearly uniform. This uniform far-field value corresponds to the Reynolds number based on the effective base viscosity associated with the imposed background shear rate according to the Carreau relation. The increase in the far-field <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline469.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline469.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }$<\/p>\n<p> with increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline470.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline470.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> is due to the reduction in the base viscosity for a fixed background shear rate in the absence of the particle, as predicted by the Carreau rheology. This behaviour is also evident in the viscosity contour plots shown in <a class=\"xref fig\" href=\"#f6\">figure\u00a06<\/a>(a\u2013d). Closer to the particle surface, however, the distribution of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline471.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"50\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline471.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l Baseline left parenthesis bold italic x right parenthesis\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }(\\boldsymbol{x})$<\/p>\n<p> shows a significant local increase compared with its far-field value for each Carreau number. This local amplification arises from the enhanced shear rates generated around the particle, which further reduce the viscosity in shear-thinning fluids. Consequently, the local viscous stresses decrease, leading to a locally more inertia-dominated region in the vicinity of the particle. Although the global channel Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline472.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline472.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> is fixed, the particle experiences a locally higher effective Reynolds number over a finite region surrounding it. In comparison with the Newtonian case at the same <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline473.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline473.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>, the shear-thinning-induced reduction in viscous stress causes the particle to effectively experience a higher Reynolds number flow in its immediate neighbourhood. As a result, the equilibrium position shifts away from the centreline. For example, configurations that remain centred in the Newtonian limit shift to an off-centre equilibrium position at finite <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline474.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline474.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, as shown in <a class=\"xref fig\" href=\"#f4\">figure\u00a04<\/a>(a). Specifically, while the Newtonian case (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline475.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"58\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline475.png\" data-zoomable=\"false\" alt=\"upper C u right arrow 0\"\/><\/p>\n<p>$Cu \\to 0$<\/p>\n<p>) yields <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline476.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"79\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline476.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r Baseline almost equals 153\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}} \\approx 153$<\/p>\n<p>, increasing the Carreau number to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline477.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline477.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p> reduces the critical Reynolds number to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline478.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"72\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline478.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r Baseline almost equals 96\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}} \\approx 96$<\/p>\n<p>, consistent with the enhanced local inertial effects discussed above. Overall these results indicates that even in the absence of flow curvature, shear thinning alone can generate localised inertia-dominated regions around the particle, destabilising the centreline equilibrium and causing off-centre migration.<\/p>\n<p class=\"p\"> Classical studies by Ho\u00a0&amp; Leal (<a class=\"xref bibr\" href=\"#ref26\">Reference Ho and Leal1974<\/a>) and Schonberg\u00a0&amp; Hinch (<a class=\"xref bibr\" href=\"#ref65\">Reference Schonberg and Hinch1989<\/a>) examined inertial migration of particles in shear and Poiseuille flows at small but finite Reynolds numbers using matched asymptotic expansions. In their framework, the flow is divided into distinct regions, one in the immediate vicinity of the particle (called the Stokes region) where viscous and pressure stresses dominate and the Stokes equations are valid, and the other far from the particle (called the Oseen region) where inertial stresses dominate. Consistency of the asymptotic analysis requires an intermediate region in which viscous and inertial stresses are comparable, which enables matching of the inner and outer solutions. In the absence of such a region, the matched asymptotic expansion approach breaks down. Further, Hood et\u00a0al. (<a class=\"xref bibr\" href=\"#ref27\">Reference Hood, Lee and Roper2015<\/a>) revisited this problem numerically and found that, even at moderate channel Reynolds numbers (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline479.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"64\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline479.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 10\"\/><\/p>\n<p>${\\textit{Re}}_c=10$<\/p>\n<p>), viscous and pressure stresses exceed inertial contributions at all radial distances from the particle, leaving no region of co-dominance and contradicting the predictions of Ho\u00a0&amp; Leal (<a class=\"xref bibr\" href=\"#ref26\">Reference Ho and Leal1974<\/a>) and Schonberg\u00a0&amp; Hinch (<a class=\"xref bibr\" href=\"#ref65\">Reference Schonberg and Hinch1989<\/a>). At higher channel Reynolds numbers (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline480.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"66\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline480.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 50\"\/><\/p>\n<p>${\\textit{Re}}_c=50$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline481.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"17\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline481.png\" data-zoomable=\"false\" alt=\"80\"\/><\/p>\n<p>$80$<\/p>\n<p>), inertial stresses increase but scale linearly with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline482.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline482.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>, acting as a passive correction rather than establishing a new dominant balance. Further, in Newtonian shear flows, particle migration at finite Reynolds numbers has been interpreted in terms of inertial screening (Ho\u00a0&amp; Leal <a class=\"xref bibr\" href=\"#ref26\">Reference Ho and Leal1974<\/a>; Fox et\u00a0al. <a class=\"xref bibr\" href=\"#ref24\">Reference Fox, Schneider and Khair2021<\/a>; Anand\u00a0&amp; Subramanian <a class=\"xref bibr\" href=\"#ref4\">Reference Anand and Subramanian2023<\/a>). Fox et\u00a0al. (<a class=\"xref bibr\" href=\"#ref24\">Reference Fox, Schneider and Khair2021<\/a>) also showed that increasing particle Reynolds number confines the particle-induced velocity disturbance to a thin region near the particle surface, thereby weakening long-range hydrodynamic interactions and particle\u2013wall coupling. Existing studies (Ho\u00a0&amp; Leal <a class=\"xref bibr\" href=\"#ref26\">Reference Ho and Leal1974<\/a>; Anand\u00a0&amp; Subramanian <a class=\"xref bibr\" href=\"#ref4\">Reference Anand and Subramanian2023<\/a>) show that, for ambient shear flow, the characteristic inertial screening length scales as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline483.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"95\" height=\"24\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline483.png\" data-zoomable=\"false\" alt=\"script l Subscript s Baseline tilde a italic Re Subscript p Superscript negative 1 divided by 2\"\/><\/p>\n<p>$\\ell _s \\sim a {\\textit{Re}}_{\\!p}^{-1\/2}$<\/p>\n<p>, or equivalently in channel scaling, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline484.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"102\" height=\"21\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline484.png\" data-zoomable=\"false\" alt=\"script l Subscript s Baseline tilde upper H italic Re Subscript c Superscript negative 1 divided by 2\"\/><\/p>\n<p>$\\ell _s \\sim H {\\textit{Re}}_c^{-1\/2}$<\/p>\n<p>. When <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline485.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"59\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline485.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline much less than 1\"\/><\/p>\n<p>${\\textit{Re}}_c \\ll 1$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline486.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"55\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline486.png\" data-zoomable=\"false\" alt=\"script l Subscript s Baseline much greater than upper H\"\/><\/p>\n<p>$\\ell _s \\gg H$<\/p>\n<p> and the walls lie within the inner Stokes region, with inertia acting as a regular perturbation. When <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline487.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"85\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline487.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals upper O left parenthesis 1 right parenthesis\"\/><\/p>\n<p>${\\textit{Re}}_c = O(1)$<\/p>\n<p> or larger, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline488.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"51\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline488.png\" data-zoomable=\"false\" alt=\"script l Subscript s Baseline less than or equivalent to upper H\"\/><\/p>\n<p>$\\ell _s \\lesssim H$<\/p>\n<p> and the walls lie in the Oseen region. In the present case, one further insight may be drawn. Since <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline489.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"85\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline489.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline greater than upper O left parenthesis 1 right parenthesis\"\/><\/p>\n<p>${\\textit{Re}}_c \\gt O(1)$<\/p>\n<p>, it follows that <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline490.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"51\" height=\"19\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline490.png\" data-zoomable=\"false\" alt=\"script l Subscript s Baseline less than or equivalent to upper H\"\/><\/p>\n<p>$\\ell _s \\lesssim H$<\/p>\n<p>, and the confining walls lie in the Oseen region. Consequently, inertial effects influence the global disturbance field rather than acting solely as a regular perturbation. Furthermore, owing to shear thinning, the viscosity decreases with increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline491.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline491.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, leading to a reduction in the effective base viscosity at the imposed shear rate as per Carreau fluid rheology. As a result, even far from the particle, the effective local Reynolds number increases in correspondence with the channel Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline492.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline492.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>. In addition, the shear rate is significantly elevated in the immediate vicinity of the particle, producing a further local reduction in viscosity and a pronounced enhancement of the local Reynolds number, as demonstrated by the spatial distributions of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline493.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline493.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }$<\/p>\n<p> shown in <a class=\"xref fig\" href=\"#f7\">figure\u00a07<\/a>. Notably, this near-particle amplification of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline494.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline494.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }$<\/p>\n<p> exceeds its far-field value. Such a localised enhancement of inertia is consistent with a stronger spatial localisation of the particle-induced disturbance. Consequently, relative to a Newtonian fluid at the same nominal channel Reynolds number, the effective inertial screening length, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline495.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"13\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline495.png\" data-zoomable=\"false\" alt=\"script l Subscript s\"\/><\/p>\n<p>$\\ell _s$<\/p>\n<p>, is further reduced in the shear-thinning case. This reduction in the screening length, together with the associated attenuation of the disturbance field, is reflected in the variation of the non-dimensional lift force across the channel height, as shown in <a class=\"xref fig\" href=\"#f5\">figure\u00a05<\/a>(a), obtained at a fixed channel Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline496.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline496.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p> with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline497.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline497.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline498.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline498.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline499.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline499.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> held constant. As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline500.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline500.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases from <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline501.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline501.png\" data-zoomable=\"false\" alt=\"0\"\/><\/p>\n<p>$0$<\/p>\n<p> (Newtonian) to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline502.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"25\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline502.png\" data-zoomable=\"false\" alt=\"100\"\/><\/p>\n<p>$100$<\/p>\n<p>, the magnitude of the lift force decreases at all fixed positions <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline503.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"33\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline503.png\" data-zoomable=\"false\" alt=\"z divided by upper H\"\/><\/p>\n<p>$z\/H$<\/p>\n<p>, leading to progressively flatter lift-force profiles at higher <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline504.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline504.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>. This reduction in lift is consistent with enhanced inertial screening of the particle-induced velocity disturbance. At larger <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline505.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline505.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, the disturbance becomes increasingly confined to the immediate vicinity of the particle surface, thereby weakening long-range hydrodynamic interactions between the particle and the confining wall, particularly wall-mediated interactions responsible for lift are weakened and reducing the net lift force. A similar trend is observed upon decreasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline506.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline506.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> (<a class=\"xref fig\" href=\"#f5\">figure\u00a05<\/a><br \/>\nb) or decreasing the power-law index <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline507.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline507.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> (<a class=\"xref fig\" href=\"#f5\">figure\u00a05<\/a><br \/>\nc), both of which intensify shear thinning. In each case, stronger shear thinning leads to a further reduction in the lift force, consistent with a greater spatial localisation of the particle-induced disturbance. Overall, our results show that, even in the absence of flow curvature, shear thinning alone is sufficient to destabilise the centreline equilibrium and trigger off-centre inertial migration. This transition can occur at relatively low channel Reynolds numbers, as shear thinning reduces the critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline508.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline508.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> compared with a Newtonian fluid. The mechanism arises from the formation of localised inertia-dominated regions around the particle, where reduced viscous stresses and increased inertial effects produce a significant local rise in <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline509.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline509.png\" data-zoomable=\"false\" alt=\"italic Re Subscript script l\"\/><\/p>\n<p>${\\textit{Re}}_{\\ell }$<\/p>\n<p>. The resulting migration behaviour differs fundamentally from that observed in Newtonian channel flows. Overall these findings highlight the important role of the shear-thinning rheology in modifying the local stress balance and in turn affecting the nature of inertial migration.<\/p>\n<p>Figure 8.<\/p>\n<p class=\"p\">Time-dependent trajectories of a particle released from different initial positions. (a) Effect of the Carreau number at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline510.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline510.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline511.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline511.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline512.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline512.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline513.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline513.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. (b) Effect of the viscosity ratio at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline514.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline514.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline515.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline515.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline516.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline516.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline517.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline517.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. (c) Effect of the power-law index at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline518.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline518.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline519.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline519.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline520.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline520.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline521.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline521.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>. (d) Influence of the Carreau number, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline522.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline522.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, on the particle migration time. The evolution of the normalised particle position, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline523.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"37\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline523.png\" data-zoomable=\"false\" alt=\"upper Z divided by upper H\"\/><\/p>\n<p>$Z\/H$<\/p>\n<p>, with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline524.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"20\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline524.png\" data-zoomable=\"false\" alt=\"upper G t\"\/><\/p>\n<p>$Gt$<\/p>\n<p> illustrates the time taken to attain the equilibrium position. Results correspond to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline525.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline525.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 50\"\/><\/p>\n<p>${\\textit{Re}}_c = 50$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline526.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline526.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline527.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline527.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p> for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline528.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline528.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig8.png\" class=\"aop-lazy-load-image\" width=\"3981\" height=\"2855\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig8.png\" data-zoomable=\"true\" alt=\"Four line graphs showing the time-dependent trajectories of a particle under different conditions.\"\/><\/p>\n<p class=\"p\">\n<a class=\"xref fig\" href=\"#f8\">Figure\u00a08<\/a>(a\u2013c) presents the lateral migration trajectories of particles released from two different initial positions, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline529.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"88\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline529.png\" data-zoomable=\"false\" alt=\"upper Z 0 divided by upper H equals 0.4\"\/><\/p>\n<p>$Z_0\/H=0.4$<\/p>\n<p> (below the centreline) and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline530.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"88\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline530.png\" data-zoomable=\"false\" alt=\"upper Z 0 divided by upper H equals 0.6\"\/><\/p>\n<p>$Z_0\/H=0.6$<\/p>\n<p> (above the centreline), within the channel. The particles are free to translate and rotate, and their trajectories are followed until they reach steady-state equilibrium positions in the <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline531.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"8\" height=\"10\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline531.png\" data-zoomable=\"false\" alt=\"z\"\/><\/p>\n<p>$z$<\/p>\n<p>-direction. In <a class=\"xref fig\" href=\"#f8\">figure\u00a08<\/a>(a), the Carreau number is varied while fixing the other parameters as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline532.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline532.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta =0.1$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline533.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline533.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n=0.25$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline534.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline534.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c=150$<\/p>\n<p>. For <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline535.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"51\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline535.png\" data-zoomable=\"false\" alt=\"upper C u equals 1\"\/><\/p>\n<p>$Cu=1$<\/p>\n<p>, the particle migrates to the centreline (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline536.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"81\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline536.png\" data-zoomable=\"false\" alt=\"upper Z divided by upper H equals 0.5\"\/><\/p>\n<p>$Z\/H=0.5$<\/p>\n<p>), independent of the initial position. As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline537.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline537.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases, however, two stable equilibria appear symmetrically about the channel centreline; a particle released from <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline538.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"88\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline538.png\" data-zoomable=\"false\" alt=\"upper Z 0 divided by upper H equals 0.4\"\/><\/p>\n<p>$Z_0\/H=0.4$<\/p>\n<p> migrates to an off-centre position between the lower wall and the centreline, whereas a particle released from <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline539.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"88\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline539.png\" data-zoomable=\"false\" alt=\"upper Z 0 divided by upper H equals 0.6\"\/><\/p>\n<p>$Z_0\/H=0.6$<\/p>\n<p> stabilises symmetrically between the centreline and the upper wall. This demonstrates that sufficiently strong non-Newtonian effects break the uniqueness of the centreline equilibrium, and the final state becomes sensitive to the initial release height. <a class=\"xref fig\" href=\"#f8\">Figure\u00a08<\/a>(b) illustrates the role of the viscosity ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline540.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline540.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p> for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline541.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline541.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu=10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline542.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline542.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n=0.25$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline543.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline543.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c=150$<\/p>\n<p>. At larger values of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline544.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline544.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p>, the centreline remains the sole equilibrium position, and trajectories are independent of initial lateral positions. Reducing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline545.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"10\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline545.png\" data-zoomable=\"false\" alt=\"beta\"\/><\/p>\n<p>$\\beta$<\/p>\n<p>, however, produces two off-centre equilibria symmetrically about the channel centreline, such that a particle released near the lower wall remains trapped below the centreline while one released near the upper wall stabilises above it. A similar trend is observed when varying the power-law index <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline546.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline546.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> (<a class=\"xref fig\" href=\"#f8\">figure\u00a08<\/a><br \/>\nc) at fixed <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline547.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline547.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu=10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline548.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline548.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta =0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline549.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline549.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c=150$<\/p>\n<p>: for <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline550.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"39\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline550.png\" data-zoomable=\"false\" alt=\"n equals 1\"\/><\/p>\n<p>$n=1$<\/p>\n<p> (Newtonian case), particles invariably migrate to the centreline, but as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline551.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"8\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline551.png\" data-zoomable=\"false\" alt=\"n\"\/><\/p>\n<p>$n$<\/p>\n<p> decreases, corresponding to stronger shear-thinning behaviour, the centreline equilibrium becomes unstable and stable off-centre equilibria emerge. To further understand the migration dynamics in comparison with the Newtonian case, we consider a parameter set for which the particle migrates to the centreline, namely <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline552.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"66\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline552.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 50\"\/><\/p>\n<p>${\\textit{Re}}_c = 50$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline553.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline553.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline554.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline554.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>, as shown in <a class=\"xref fig\" href=\"#f8\">figure\u00a08<\/a>(d). It can be observed that as the Carreau number increases from <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline555.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline555.png\" data-zoomable=\"false\" alt=\"upper C u equals 0.1\"\/><\/p>\n<p>$Cu = 0.1$<\/p>\n<p> to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline556.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"25\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline556.png\" data-zoomable=\"false\" alt=\"100\"\/><\/p>\n<p>$100$<\/p>\n<p>, the time required for the particle to reach the centreline decreases. In addition to that, we have observed that the streamwise distance travelled by the particle before reaching its equilibrium position is also reduced. This behaviour indicates that in a shear-thinning fluid the particle experiences a lower effective hydrodynamic force than its Newtonian counterpart. The reduction in viscosity with increasing shear rate decreases the overall viscous resistance acting on the particle, allowing it to migrate more rapidly and over a shorter streamwise distance toward the centreline. Taken together, these trajectories provide direct numerical confirmation of the multiple stable equilibrium positions predicted by the lift-force analysis shown in <a class=\"xref fig\" href=\"#f5\">figure\u00a05<\/a>(a\u2013c). The viscosity contours (<a class=\"xref fig\" href=\"#f6\">figure\u00a06<\/a>) and the local Reynolds number distributions (<a class=\"xref fig\" href=\"#f7\">figure\u00a07<\/a>) further clarify the underlying mechanism, demonstrating that shear thinning enhances local inertial effects through viscosity reduction in high-shear regions around the particle. As a consequence, the migration dynamics and equilibrium locations differ fundamentally from the Newtonian case, and particle migration is governed primarily by the coupled influence of fluid rheology and inertia. All the above results correspond to a confinement ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline557.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline557.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>. It is therefore important to examine how these equilibrium states and migration characteristics are modified as the degree of confinement is varied. This aspect is addressed in the following section.<\/p>\n<p>3.2. Effect of confinement ratio<\/p>\n<p class=\"p\"> To elucidate the role of geometric confinement on inertial migration, we examine the effect of the confinement ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline574.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline574.png\" data-zoomable=\"false\" alt=\"kappa equals a divided by upper H\"\/><\/p>\n<p>$\\kappa = a\/H$<\/p>\n<p>, which quantifies the particle size relative to the channel height. In the present study, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline575.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline575.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p> is varied between <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline576.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"31\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline576.png\" data-zoomable=\"false\" alt=\"0.05\"\/><\/p>\n<p>$0.05$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline577.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"23\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline577.png\" data-zoomable=\"false\" alt=\"0.2\"\/><\/p>\n<p>$0.2$<\/p>\n<p>, corresponding to weak confinement (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline578.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"94\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline578.png\" data-zoomable=\"false\" alt=\"kappa equals 0.05 comma 0.1\"\/><\/p>\n<p>$\\kappa = 0.05, 0.1$<\/p>\n<p>) and strong confinement (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline579.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline579.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>). <a class=\"xref fig\" href=\"#f9\">Figure\u00a09<\/a>(a) shows the normalised stable equilibrium position as a function of the Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline580.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline580.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> for different confinement ratios at fixed rheological parameters <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline581.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"60\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline581.png\" data-zoomable=\"false\" alt=\"upper C u equals 10\"\/><\/p>\n<p>$Cu = 10$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline582.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline582.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline583.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline583.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. It is evident that the critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline584.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline584.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> increases with increasing confinement. In particular, for strong confinement (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline585.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline585.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p>), the onset of off-centre migration occurs at a significantly higher <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline586.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline586.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p> compared with the weakly confined cases (<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline587.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"94\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline587.png\" data-zoomable=\"false\" alt=\"kappa equals 0.05 comma 0.1\"\/><\/p>\n<p>$\\kappa = 0.05, 0.1$<\/p>\n<p>), indicating a stabilising influence of the channel walls. The influence of shear-thinning at a fixed confinement is illustrated in <a class=\"xref fig\" href=\"#f9\">figure\u00a09<\/a>(b), which compares equilibrium positions for two Carreau numbers at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline588.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"53\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline588.png\" data-zoomable=\"false\" alt=\"kappa equals 0.1\"\/><\/p>\n<p>$\\kappa = 0.1$<\/p>\n<p>, with <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline589.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline589.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline590.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline590.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. At low <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline591.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"26\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline591.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c\"\/><\/p>\n<p>${\\textit{Re}}_c$<\/p>\n<p>, the particle remains centred; however, beyond a critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline592.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline592.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>, a symmetry-breaking bifurcation occurs and stable off-centre equilibrium positions emerge. Importantly, increasing the Carreau number leads to a systematic reduction in <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline593.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline593.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>, consistent with the trends observed under stronger confinement. This demonstrates that shear thinning accelerates the onset of inertial migration irrespective of the confinement level. <a class=\"xref fig\" href=\"#f9\">Figure\u00a09<\/a>(c) summarises these trends by showing the variation of the critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline594.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline594.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> with the Carreau number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline595.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline595.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> for confinement ratios <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline596.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"94\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline596.png\" data-zoomable=\"false\" alt=\"kappa equals 0.05 comma 0.1\"\/><\/p>\n<p>$\\kappa = 0.05, 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline597.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"23\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline597.png\" data-zoomable=\"false\" alt=\"0.2\"\/><\/p>\n<p>$0.2$<\/p>\n<p>, at fixed rheological parameters <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline598.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline598.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline599.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline599.png\" data-zoomable=\"false\" alt=\"beta equals 0.5\"\/><\/p>\n<p>$\\beta = 0.5$<\/p>\n<p>. In the limit of very small <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline600.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline600.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, corresponding to a flow approaching the Newtonian regime, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline601.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline601.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> decreases with decreasing confinement ratio and approaches closer to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline602.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"79\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline602.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r Baseline almost equals 148\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}} \\approx 148$<\/p>\n<p> specifically when <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline603.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline603.png\" data-zoomable=\"false\" alt=\"kappa equals 0.05\"\/><\/p>\n<p>$\\kappa = 0.05$<\/p>\n<p>. This value is in good agreement with the analytically obtained critical Reynolds number reported by Anand\u00a0&amp; Subramanian (<a class=\"xref bibr\" href=\"#ref4\">Reference Anand and Subramanian2023<\/a>) for a neutrally buoyant particle in a Newtonian fluid. As the Carreau number increases, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline604.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline604.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> decreases markedly, indicating an enhanced role of shear thinning in promoting the instability. Furthermore, for a fixed value of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline605.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline605.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>, reducing the confinement ratio, equivalently increasing the channel height relative to the particle size, leads to a further reduction in <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline606.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline606.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p>. Overall, the dependence of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline607.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline607.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> on <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline608.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline608.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p> reflects a balance between wall-induced hydrodynamic interactions and viscosity-driven asymmetries. Under strong confinement, enhanced particle\u2013wall interactions generate stabilising wall-induced lift forces that delay the onset of bifurcation. In contrast, weak confinement diminishes wall effects, allowing non-Newtonian modifications of the flow field to dominate the lateral force balance and trigger earlier symmetry breaking. It is further observed from <a class=\"xref fig\" href=\"#f9\">figure\u00a09<\/a>(c) that, at lower Carreau numbers, corresponding to the near-Newtonian limit, the variation of the critical Reynolds number <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline609.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline609.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> with confinement ratio is relatively weak. However, as <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline610.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline610.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases, a pronounced dependence of <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline611.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"32\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline611.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c r\"\/><\/p>\n<p>${\\textit{Re}}_{{cr}}$<\/p>\n<p> on confinement emerges, indicating that confinement effects become significantly amplified in the shear-thinning regime.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig9.png\" class=\"aop-lazy-load-image\" width=\"3954\" height=\"2804\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig9.png\" data-zoomable=\"true\" alt=\"Three line graphs depict the relationship between normalized equilibrium position, critical Reynolds number, and Carreau number.\"\/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig10.png\" class=\"aop-lazy-load-image\" width=\"3896\" height=\"1236\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_fig10.png\" data-zoomable=\"true\" alt=\"Two line graphs depict variations in normalized particle velocities with the Carreau number.\"\/><\/p>\n<p class=\"p\"> Next, we look at the translational and angular velocities of the particle at steady state. <a class=\"xref fig\" href=\"#f10\">Figure\u00a010<\/a>(a, b) shows the magnitude of particle translational velocity <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline620.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"72\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline620.png\" data-zoomable=\"false\" alt=\"left parenthesis upper U equals StartAbsoluteValue bold italic upper U EndAbsoluteValue right parenthesis\"\/><\/p>\n<p>$(U=|\\boldsymbol{U}|)$<\/p>\n<p> normalised by the wall velocity <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline621.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"20\" height=\"15\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline621.png\" data-zoomable=\"false\" alt=\"upper V Subscript w\"\/><\/p>\n<p>$V_w$<\/p>\n<p>, and the magnitude of angular velocity <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline622.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"75\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline622.png\" data-zoomable=\"false\" alt=\"left parenthesis upper Omega equals StartAbsoluteValue bold italic upper Omega EndAbsoluteValue right parenthesis\"\/><\/p>\n<p>$(\\varOmega = |\\boldsymbol{\\varOmega }|)$<\/p>\n<p> normalised by the imposed shear rate <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline623.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"13\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline623.png\" data-zoomable=\"false\" alt=\"upper G\"\/><\/p>\n<p>$G$<\/p>\n<p>, for varying Carreau numbers as a function of confinement ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline624.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline624.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p>. The results correspond to <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline625.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"74\" height=\"16\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline625.png\" data-zoomable=\"false\" alt=\"italic Re Subscript c Baseline equals 150\"\/><\/p>\n<p>${\\textit{Re}}_c = 150$<\/p>\n<p>, <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline626.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"17\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline626.png\" data-zoomable=\"false\" alt=\"beta equals 0.1\"\/><\/p>\n<p>$\\beta = 0.1$<\/p>\n<p> and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline627.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"62\" height=\"13\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline627.png\" data-zoomable=\"false\" alt=\"n equals 0.25\"\/><\/p>\n<p>$n = 0.25$<\/p>\n<p>. It is observed that both the translational and angular velocities decrease with increasing <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline628.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline628.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p>. Furthermore, as the confinement ratio <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline629.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline629.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p> decreases (i.e. for wider channels), the translational velocity decreases, whereas the rotational velocity increases. This behaviour is linked to the shift in the equilibrium position of the particle. For the present parameter set, all cases except <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline630.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"54\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline630.png\" data-zoomable=\"false\" alt=\"kappa equals 0.2\"\/><\/p>\n<p>$\\kappa = 0.2$<\/p>\n<p> at <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline631.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"65\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline631.png\" data-zoomable=\"false\" alt=\"upper C u equals 0.1\"\/><\/p>\n<p>$Cu = 0.1$<\/p>\n<p> migrate toward off-centre equilibrium positions between the bottom wall and the centreline, since the particle is initially released in the lower half of the channel. As <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline632.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"21\" height=\"12\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline632.png\" data-zoomable=\"false\" alt=\"upper C u\"\/><\/p>\n<p>$Cu$<\/p>\n<p> increases and <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/06\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline633.png\" class=\"aop-lazy-load-image mathjax-alternative mathjax-alt-graphic mathjax-off\" width=\"9\" height=\"9\" data-original-image=\"\/binary\/version\/id\/urn:cambridge.org:id:binary:20260622115004475-0002:S0022112026117376:S0022112026117376_inline633.png\" data-zoomable=\"false\" alt=\"kappa\"\/><\/p>\n<p>$\\kappa$<\/p>\n<p> decreases, the equilibrium position moves progressively closer to the wall. The reduced local streamwise fluid velocity near the wall leads to a decrease in translational speed, while the enhanced velocity gradients in the wall vicinity promote increased particle rotation.<\/p>\n","protected":false},"excerpt":{"rendered":"3.1. Effect of Carreau number, viscosity ratio and power-law index We begin by examining the influence of shear&hellip;\n","protected":false},"author":2,"featured_media":757753,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[49,48,314,66],"class_list":["post-757752","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-ca","tag-canada","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/757752","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=757752"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/757752\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/757753"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=757752"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=757752"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=757752"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}