A Passive Aerodynamic Strategy for Sustainable Mobility: Harnessing Biomimetic Dimpling to Improve Vehicle Fuel Economy

This study explores biomimetic surface dimpling as a passive aerodynamic strategy for sustainable vehicle design. Inspired by natural flow control mechanisms, a 1:30 scale car model was developed with varying dimple depths (1.25, 2.5, and 5 mm) and placements (top, side, bottom). Ten high-precision SLA 3D-printed prototypes were tested in a custom-built subsonic wind tunnel at 2.7 m/s, with lift and drag forces measured using calibrated load cells and validated through computational fluid dynamics (CFD) simulations. We observed that side-mounted dimples with a 2.5 mm depth achieved optimal performance, reducing aerodynamic drag by approximately 25% compared to the smooth control model. CFD visualizations confirmed coherent streamwise vortices that delayed flow separation and enhanced pressure recovery, demonstrating the effectiveness of this mechanism. As a zero-energy passive modification, this approach directly supports UN Sustainable Development Goals 7 and 9 by improving energy efficiency and reducing emissions. The findings establish a scalable, nature-inspired framework for advancing vehicle aerodynamics, offering immediate applications for both electric and conventional vehicles in achieving sustainable mobility.