Effect of Wheel Rotational Speed on the Drag of a Sport Utility Vehicle Coupé and the Aerodynamic Evaluation of Wheelsets 2022-01-5041

Wind tunnel measurements carried out as part of the development of the Porsche Cayenne Coupé showed a significant decrease in the drag coefficient with increasing wind or simulation speed for certain vehicle configurations. The influence of wheel rotation was identified as the cause. Systematic investigations were then conducted with different wheelsets at wind speeds of up to 300 km/h. The results show that primarily the rotation of the rear wheels is responsible for the decrease of the drag coefficient with increasing speed. The comparison of the individual wheelsets with each other shows that different rim-tire combinations lead to different drag gradients. The consequences of this for the aerodynamic evaluation of wheel-tire combinations are shown and discussed.