Flow Characteristics of a Van during Cross-Wind and Overtaking Process 990022
Wind tunnel experiments in an idealized van model is conducted to study the flow characteristics in different cross-wind and overtaking conditions. Static pressure distribution along the mid longitudinal and horizontal sections of the model are performed at yaw angles of 0° (no cross-wind), 10°, 20° and 30° in a 0.6m by 0.6m, low speed, suction type wind tunnel. The overtaking process is simulated by using two similar models simultaneously, one dummy model and other the measuring model in various in-line and off-center conditions. Cross wind results in higher pressure in the wind-ward side as compared to the lee-ward side, thereby causing a strong yawing moment. The stagnation region shifts towards the wind-ward side, with increase in yaw angle. During overtaking process, the proximity of another vehicle decreases the pressure distribution on top and at the overtaking side of the vehicle, possibly due to the venturi like effect.