초경량 전기자동차의 주행거리 극대화를 위한 공기역학적 최적화 설계연구

Drag reduction of a running vehicle is very important issue for energy savings and emission reduction. Especially for a solar powered electric vehicle, the drag reduction and weight lightening are two serious problems to be solved to extend the driving distance with the given energy source. In this study, the ground effect of an airfoil shaped road vehicle was studied for an optimum body design of an ultra-light solar powered electric vehicle. Clark-Y airfoil shape was adopted to the body shape of the model vehicle to reduce aerodynamic drag. From the study, it was found that the drag of the model vehicle was reduced as the height(h) between ground and the lower surface of the model vehicle was decreased. It is due to the reduction of the down-wash decreasing the induced drag of the vehicle. The lift was also decreased as the height was decreased. It is due to the turbulent boundary layer developed beneath the vehicle body. The drag is classified into two types; form drag and friction drag. The fraction ratio of form drag to friction one is 76 to 24 on the model vehicle. As the height(h) of the model vehicle increases the form drag increase but the friction drag is in reverse.