Aerodynamic Sensitivity Analysis of Wheel Shape Factors 2019-01-0667

Wheels play an important role in determining the aerodynamic drag of passenger vehicles. This is because the contribution of wheels to aerodynamic drag comes from not only the wheels themselves, but also from the interference effect between wheel wakes and the base wake. As far as the authors are aware, there have been no reports about aerodynamic drag sensitivity to wheel shape factors for different vehicle types and different exterior body shapes. The purpose of this study was to clarify C_D sensitivity to wheel shape factors for a sedan and an SUV, including different rear fender shapes. Many different wheel configurations were investigated in terms of the C_D, base pressure and flow fields in wind tunnel tests. Multiple regression analyses were conducted to clarify C_D sensitivity to each wheel shape factor based on the test data. This study revealed high C_D sensitivity factors for both the sedan and SUV. The findings show that wheel shape factors and related C_D sensitivities provide design guidelines for reducing aerodynamic drag.