Evaluation of wind tunnel interference on numerical prediction of wheel aerodynamics

For a passenger vehicle, approximately 25% of the total aerodynamic drag originates from the wheels, making the aerodynamics of wheels a significant factor for the overall performance of a vehicle. To understand the complex flow field created by the rotational condition and geometry of these bluff-bodies, numerical simulations are often used. However, computations are frequently performed in domains that replicate open road conditions, differing from the conditions of wind tunnels. Therefore, to properly validate a CFD procedure and to correlate physical tests to numerical results, interference effects of the wind tunnel need to be investigated and their impact on the aerodynamics of wheels analysed and compared to that of open road calculations.In this study, numerical simulations on the DrivAer model were performed using different tyres and rims in both open road conditions and with the inclusion of a detailed model of a slotted walls wind tunnel. The results of the simulations are compared to experimental data, consisting of forces and flow field measurements. It was found that the inclusion of the wind tunnel in the computations improves the prediction of the flow fields, resulting in better prediction of both the absolute drag values and the drag deltas between configurations.

Automated summary

The aerodynamics of wheels is a significant factor for the overall performance of a vehicle, and approximately 25% of the total aerodynamic drag comes from the wheels. This study used numerical simulations to investigate the impact of different tires and rims on the aerodynamics of a vehicle, and compared the results to experimental data. It was found that including a wind tunnel model in the simulations improved the prediction of the flow fields.