Effects of Tire Attributes on the Aerodynamic Performance of a Generic Car–Tire Assembly¹

The effect of tires on the overall aerodynamic drag in a car–tire assembly has been studied and deemed considerable from past studies. It has been shown that it is important to understand how the vehicle body and the tires influence the flow structures generated. Previous studies focused on the tire attributes that have an impact on the aerodynamic performance of the vehicle. These tire attributes, however, have not been studied extensively. This paper studies the impact that specific tire attributes have on the overall aerodynamic drag on the vehicle through a systematic sensitivity study. In this study, the DrivAer model is used due to the extensive research that has been done on the model. A baseline computational fluid dynamics model of the tire–vehicle assembly of the DrivAer model is simulated using ansysfluent in the open road domain to understand the flow structures around the body of the vehicle. Simulations are done on the fastback configuration of the DrivAer model with a smooth underbody. Coefficient of drag and coefficient of pressure results from the simulation are validated from experimental data. Data from the simulations and design of experiments are used to quantitatively compare the drag contribution of different parameters of the tire. The sensitivity analysis of the tire–vehicle assembly model performed gives a better insight into the modeling techniques that can be used on a car–tire assembly, as well as the impact of the parameters that could be selected for future tire model optimization.