DESIGN, EXPERIMENTAL STUDIES, AND CFD INVESTIGATIONS OF BIO-INSPIRED SLOTTED REAR DIFFUSER ATTACHMENT ON CAR MODEL FOR ENHANCING AERODYNAMIC PERFORMANCE

Abstract

The performance enhancement of vehicle design is still a challenging phenomenon for technologists. A suitable pathway for performance enrichment is naturally available in living species. One adaptable design solution arrived through the penguin microbubble concept, which was used to reduce drag. The present work attempts to design rear-slotted diffuser attachments on car models to reduce drag force through the diversion of air. The drag reduction enhances the vehicle’s aerodynamic performance and reduces lift force to increase stability. Normally, high-speed vehicle performance and stability are determined by aerodynamic forces exerted on the body surface. The higher level of drag and lift forces leads to more fuel utilization and, in the case of electric vehicles, more power consumption. The drag force on the vehicle is mainly due to the formation of the wake region behind the body in the downstream region. The above forces are reduced using a rearward-slotted diffuser at the rear end underneath the vehicle. The aerodynamic performance of the vehicle models was estimated through wind tunnel experiments and numerical simulation for various wind speeds. The experimental work was conducted on selected car models with and without rearward slotted diffusers to compare the forces and performances of vehicle models. Interestingly, increased pressure was observed downstream of the vehicle while providing a slotted diffuser, consequently diminishing the wake area behind the vehicle. The drag and lift coefficient reduction were attained as 4.74% and 11.02% at 50 m/s (180 km/hr) on the chosen vehicle model. Also, a significant reduction in fuel consumption was calculated at higher speeds while attaching a slotted diffuser at the rear end of the car.