Development of Active Aerodynamic Improvement Devices for Automobiles

Abstract

Study on the steady blowing system using state-of-the-art of Computational Fluid Dynamics (CFD) technique based on an open domain CFD software, OpenFOAM[1], is performed to reduce vehicle aerodynamic drag. Realistic vehicle model, DrivAer[2], is used for the validation of current CFD technique. Both the aerodynamic drag coefficient and the surface pressure distributions were compared between current CFD and reference wind tunnel test. It was found that CFD method used in this study is reliable tool for the forecasting of the aerodynamic drag coefficient. The influence of steady blowing from the sharp edge of the roof end is investigated based on DrivAer Estate back model. Parametric study was performed by changing blowing speed at the three different Reynolds number. It was shown that the steady blowing leads around 3% drag reduction by enhancing wake balance especially, reinforcing downwash flow from the roof. Therefore it would be concluded that steady blowing is a useful device to reduce aerodynamic drag of automobile.