Aerodynamic Drag Simulation and Validation of a Crossover

Aerodynamic simulation using commercial CFD (Computational Fluid Dynamics) codes is now an integral part of the vehicle design process. Aerodynamic prediction and vehicle development program runs in parallel. This requires a good agreement between experimental measurements and CFD prediction of aerodynamic behavior of a vehicle. The comparison between experimental and simulation results show differences, as it may not be possible to replicate effect of all the wind tunnel parameters in the simulation.

This paper presents the details of aerodynamic simulation process of a Crossover and its validation with the experimental results available from the wind tunnel tests. The results are compared for different configurations such as- closing the grille openings, removing the rearview mirror, adding ski-rack and using different tyres. This study also includes the effect of different wind speeds and yaw angles on the coefficient of drag. A detailed investigation of the flow field data such as surface pressure and wind speed for two different types of wind tunnels is shown. It is observed that the surface pressures and forces are influenced by the type and size of the wind tunnel, also the effect of wind tunnel blockage is demonstrated by comparing the results of two different wind tunnels.