As indicated by previous studies, many attributes of tires have been shown to have an impact on tire aerodynamic drag. However, the way these attributes affect tire aerodynamics has not been systematically investigated to date. It is not clear which tire attributes have the most significant impact on aerodynamic drag. Therefore, a sensitivity study of the effects of tire attributes on tire aerodynamic performance is proposed in this study. This sensitivity study improves the understanding of flow structures and mechanisms around tires.
First, a baseline CFD model of a tire is created and validated by experimental data. In the computational model, the tire is positioned in a wind tunnel to match the experimental testing configuration. A hybrid boundary condition method is used to simulate a rotating tire. Based on the validated baseline model, various tire attributes are considered and compared in the study proposed. The tire attributes considered include tire width, tire side wall profile, lateral grooves, and open rim design. There are five cases in total for the sensitivity study. Then the effects of these attributes on the tire aerodynamic drag are calculated and compared. The most influencing feature is then identified. The results show that a smoothed side wall profile with smaller radius can improve the aerodynamic performance of an isolated tire. On the other hand, the influence of lateral grooves on tire aerodynamic performance is limited. The force integrated from all lateral groove surfaces only account to less than 2% of the total tire drag force. Additionally, an idealized open rim design changes the flow structure significantly, which leads to the increase of aerodynamic drag. The force integrated on the rim surface account for up to 20% of the overall tire drag force.