Numerical Simulations of a Car Underbody: Effect of Front-Wheel Deflectors

Numerical simulations of a detailed car underbody have been carried out using a commercial code. The objective of the present study was to decrease vehicle aerodynamic drag by placing front-wheel deflectors and to understand the influence of these extra details on the underbody flow. A base-model and five different configurations have been investigated and analyzed. The results are presented in terms of drag and front and rear lift values. In addition, the drag contribution of individual parts/areas of the underbody is also presented, which helps a great deal the understanding of the effect of front-wheels deflectors on the underbody of a vehicle. The results show that, in most cases, front-wheel deflectors are very effective in reducing overall aerodynamic drag (values around dCd = −0.010 were calculated, which correspond to a 4% reduction in drag). However, the deflector itself has a significant contribution to the final drag, and its shape and location should be optimized in order to maximize its effect.