Droplets are where a great deal of interesting fluid mechanics happens, and the interface is where it is decided. How a drop breaks, how it lands, how far it spreads and what it leaves behind when it dries are all governed by what occurs over a few micrometres of interface, yet they set the performance of combustors and propulsion systems, inkjet and additive manufacturing, spray cooling, agricultural sprays, coatings, diagnostics and microfluidic devices. The last decade has brought high speed imaging, interface resolved simulation and engineered surfaces to the point where the underlying physics can finally be observed and predicted rather than inferred.This Special Topic brings together current work across four connected themes: droplet breakup and instabilities from hypersonic to microfluidic conditions, impact of droplets on natural and engineered surfaces, wetting and dewetting on functionalised, patterned and liquid infused surfaces, and drying and pattern formation in simple and complex droplets. Experimental, computational and theoretical contributions are equally welcome, as are Perspectives, Tutorials and Reviews. The collection is associated with the International Conference on Interfacial Phenomena in Droplets, to be held at the Indian Institute of Science, Bangalore, on 5 to 7 October 2026, but submission is open to all and is not restricted to conference participants.
Saptarshi Basu, Professor, Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Aloke Kumar, Associate Professor, Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Ranjan Ganguly, Department of Power Engineering, Jadavpur University, Kolkata, India