Abstract
The flow around a van-type vehicle passing through cross wind is visualized to analyze its cross wind stability. The vehicle is driven at 120 km/h across a 45m long cross wind generator which blows crosswind of 15m/s. Several hundred tufts are attached onto the side panel of the vehicle and their motion is taken by a high-speed video tape recorder. The results show that a strong vortex is generated on the leeward side while passing through crosswind in the case of the original vehicle. This is why a considerable value of the yaw-rate is observed with it. On the other hand, in the case of the vehicle with some aerodynamic attachments, the flow on the leeward side is separated and the suction pressure there is reduced and the yaw-rate value is reduced considerably. It is concluded that the changing of the vortex on the leeward side into the separated flow is effective in improving the crosswind stability.
