If you make a smooth surface just a tiny bit rough, you can actually cut its air resistance by almost half.
March 26, 2026
Original Paper
DMR effect on drag reduction of a streamlined body measured by Magnetic Suspension and Balance System
arXiv · 2603.23843
The Takeaway
Common sense suggests that the smoother a surface is, the faster it can move through the air, but this experiment proves the opposite. By adding tiny 'micro-roughness' bumps only 1% as thick as the air layer, researchers delayed the onset of turbulence and reduced aerodynamic drag by a staggering 43.6%.
From the abstract
This study experimentally investigates the aerodynamic drag reduction capabilities of distributed micro-roughness (DMR) coatings on a streamlined model, utilising the 1-m magnetic suspension and balance system (MSBS) at Tohoku University. Previous direct numerical simulations (DNS) indicated that DMR can mitigate turbulent-energy growth by suppressing Tollmien--Schlichting (TS) waves and influencing the breakdown of streamwise vortices. The present work provides the first experimental validation