Influence of Wheel Rotation and Tire Geometry Details on Numerical Prediction of Vehicle Aerodynamics Under Crosswind Conditions

Wheels and tires contribute around 25% of the total aerodynamic drag of a vehicle. Most research have conducted the simulation accuracy around wheels and tires with rotations involving steady wind speeds and zero-yaw angles, which differ from real-world driving conditions.In this study, the appropriate simulation conditions for accurately predicting the effects of quasi-steady changes in yaw angle on Cd and airflow characteristics around a vehicle with rotating tires and wheels were clarified. Simulations were performed under three distinct conditions while varying the levels of tire geometry representation and the methods of tire and wheel rotation; the results were evaluated against wind tunnel measurements to determine the proper simulation conditions for enhancing prediction accuracy.The results of the study demonstrate that improving the reproduction accuracy of the tire shape and rotation of the wheel and groove is crucial for improving the prediction accuracy of Cd and airflow during yaw angle changes. The changes in Cd and airflow can be reproduced when the yaw angle is changed by reproducing the tire geometry detail using a sliding mesh for wheel rotation and a moving reference frame for groove rotation.