Aerodynamic performance of bio-inspired vortex generator on automobiles

The aerodynamic efficacy of using the precise fin morphologies of marine creatures as vortex generators (VGs) remains a largely unexplored area of study. The marine creatures have shaped their body and fins to enhance hydrodynamic performance. This study investigates the aerodynamic performance of novel bio-inspired VGs derived from the fin designs of whale sharks and dolphins. Using computational fluid dynamics (CFD) simulations on a 1:16 scaled Audi A4 model, this research evaluates the effectiveness of three bio-inspired designs − Whale Shark Fin-1 (WSF-1, with notch), Whale Shark Fin-2 (WSF-2, without notch), and Dolphin Fin (DF) − in comparison to a baseline model and a conventional Audi Q7 VG. The analysis focuses on how each VG design influences drag and lift coefficients, flow structures, pressure distribution, and skin friction at speeds of 80 km h⁻¹ and 108 km h⁻¹ corresponding to Reynolds numbers (Re) of 4.3 × 10⁵ and 5.9 × 10⁵, respectively. The results demonstrate that the WSF-2 VG achieves the most significant aerodynamic enhancement, particularly at 80 km h⁻¹, where it reduced the C_D by 7.5% and increased the downforce by 3.85%. This superior performance is attributed to its ability to generate coherent vortices that effectively delay flow separation, reduce the low-pressure wake region, and maximize pressure recovery on the vehicle’s rear. These findings highlight the potential of biomimetic design in developing passive flow control devices to improve vehicle fuel efficiency and stability.