Aerodynamic Analysis of Rear Diffusers for a Passenger Car Using CFD

Increasing environmental pollution and fuel prices are the driving forces for automotive manufacturers to develop energy efficient vehicles with lower emissions. Improving the aerodynamic characteristics and reducing the aerodynamic drag resistance of a car is the easiest and cost efficient way to handle this problem. A conventional device to improve the aerodynamics that is used on sports and racing cars is a diffuser which improve the pressure recovery on the underbody. In this study, the drag reduction effect of a diffuser has been studied on a sedan car. To understand the effects of the diffuser, computational fluid dynamics (CFD) simulations has been performed. In these simulations, diffusers with different angles were simulated to find most effective drag reduction configuration. Analyses have shown that, it is possible to improve the aerodynamic characteristics by implementing diffusers at the vehicle’s underbody.