Effect of biomimetic fish forms on minibus aerodynamics: CFD and wind tunnel comparison

This research explores the aerodynamic benefits of incorporating biomimetic design principles into commercial minibus bodies by mimicking the cranial morphology of select aquatic species. Inspired by the pronounced head structures and maneuverability of the hump head wrasse, green hump head parrotfish, and flowerhorn fish, three alternative vehicle geometries were developed and compared to a conventional reference model. Computational fluid dynamics (CFD) analyses were performed using the k–ω SST turbulence model, and experimental validation was conducted via wind tunnel testing on a 1:28 scale prototype. Among the configurations, the hump head wrasse-based model exhibited the most favorable aerodynamic behavior, achieving a 16.03% reduction in drag coefficient relative to the baseline. This improvement corresponds to an estimated 8% decrease in fuel consumption, translating to approximately 324 liters of annual savings for a vehicle operating over 45,000 km, and a projected reduction of 748 kg of CO₂ emissions. The results demonstrate that biologically derived shapes can contribute meaningfully to the aerodynamic refinement of ground vehicles, with direct implications for environmental sustainability and energy efficiency.