自動車のエンジン冷却風による空気力学的悪影響の低減

抄録

The purpose of this research is to clarify the change of characteristics of aerodynamic drag and lift of a car by the engine loading system (engine arrangement) and the air inlet system (opening area and position) in wind-tunnel experiments and to consider a method to reduce the drag and lift. A simplified 1/5 scale car model was generated with reproduction of the engine room covered with the transparent acryl externals for visualization. In the wind-tunnel experiments, the moving-belt ground board was adopted to capture ground effects with force measurements by use of load cells. As results, with enlargement of the opening area, the drag increased overall although depending largely on the engine loading system and the opening position, and the front lift increased. As the exhaust air to the underfloor increased, the turbulent intensity measured by RMS increased and the velocity decreased. Consequently, it is considered that the pressure on the front surface, and therefore the drag, increases and that the downward momentum of the air, and therefore the lift, increases.