For modern car design, aerodynamics are important. Incredibly important, even. Why else would carmakers spend so much time making aerodynamically-sound flush door handles that are overcomplicated garbage otherwise? Or those tiny fins and vortex generators molded into taillight lenses or all of the time and effort spent in wind tunnels fine-tuning and refining, all so a car can be as slippery as possible through the wind? A car with a low coefficient of drag is a more efficient car, and a more efficient car goes further on a drop of gas or a battery cell. And that means more range, which, for electric cars especially, is the kind of magic number car buyers love to look at.
Now that you’re thinking about that, reach over to your nightstand and find in your big stack of Field and Stream and Oui magazines the latest issue of the Journal of Fluid Mechanics, the May 7, 2026 issue, which has a paper from Associate Professor Aiko Yakeno of the Institute of Fluid Science, Tohoku University. This paper is interesting because it knocks on its ass over 80 years of accepted aerodynamics beliefs, specifically the idea that smoother is always better.
Yakeno and his team found that by applying “microscopic, irregular roughness (DMR) to the surface of a streamlined model” they were able to reduce air resistance by a staggering 43.6%! Let’s repeat that number, but in bold, just because that’s a freaking massive improvement: 43.6%!
Image: Tohoku University
That’s right, the researchers found that a specifically roughened surface had dramatically less air resistance than a completely smooth surface, and this effect seems to be different than other observed surface-level effects, like the shark skin-inspired surface systems that use uniformly-shaped “denticles” to reduce drag. The microscopic roughness approach led to a “suppression of wall friction resistance itself,” which differs from other drag-reducing methodologies.
Part of what makes this study so interesting has to do with how the results were measured. Unlike most conventional wind tunnel tests that require support rods to hold up the models to be tested, which creates all sorts of turbulence, the team used a “1m Magnetic Support Balance (MSBS)” system that levitates the aero testing models with magnetic fields, and looks a bit like magic in photos:
Image: Tohoku University
See that rocket-like object hovering in the middle of the tunnel there? It’s actually levitating there, held in place by magnetic fields. This method allowed the researchers to take the precision measurements necessary to conclude the level of drag reduction happening with their microscopically-roughened surfaces.
So what could this mean for cars? The initial applications of this potential breakthrough seem to be targeted to the aerospace industry, but I don’t see any reason why this wouldn’t end up in automotive design. After all a 40+% improvement in drag is huge, especially for electric vehicles. So what could the application of these methods look like in cars?
If we look at how the surface roughening process is described in the paper, we can get some idea:
Note 1. DMR (Distributed Micro-Roughness): A surface texture characterized by the irregular distribution of random micron-sized fine irregularities across the entire surface. In this study, two types were used: a convex pattern using 38-53 μm glass beads and a concave pattern using sandblasting. Unlike the “turbulence-promoting roughness” that has been a problem in conventional roughness research, DMR is a new concept of surface texture that delays transitions and reduces frictional resistance under specific conditions.
So, based on this, a car body with these roughening methods employed would likely look pretty much like any other car, but there could be a sort of…matte effect to the surfacing? (That’s why I put that Kia EV4 in the topshot: it’s matte.) I’m just speculating here, but I suspect that while this surface roughening is likely too small and subtle to feel with your hand, it would affect how light plays upon the surfaces of the car, and I’d suspect the effect would be to diffuse the light, leaving a decidedly non-shiny appearance.
That seems a small price to pay for such a potentially dramatic decrease in drag, though. Besides, I bet some matte finish-looking cars could be pretty cool. They might even look a little velvety? And I bet when they get wet or icy the visual differences would be even more pronounced!
Some of you may be thinking that this sounds similar to the golf ball dimples experiment famously undertaken by the MythBusters crew, where they managed to make a car more fuel efficient via the application of golf ball-like dimples:
This is actually a very different effect to what is going on in the Tohoku study. Golf ball dimpling helps to reduce drag and increase lift due to a boundary layer effect, which is not the same thing that is happening in the study using microscopically roughened surfaces.
We’re likely years away from any automotive application of this research, but it’s fun to start thinking about it now.
Top graphic images: Tohoku University; DepositPhotos.com; Kia