Vortex behind A-Pillar of Car and Wind Noise

Abstract

When a car runs at high speed, "wind noise" is generated. It is said that the vortex behind the A-pillar of the car is strongly correlated with the generation of the wind noise.
A flow visualization method has been developed. A laser light sheet and soap bubbles are used as the light source and the tracers, respectively. The flow field around the A-pillar of a 1/5 scale car model is visualized by this method.
As a result, it is seen that the shape of the vortex varies as the yaw angle or the A-pillar shape changes. Furthermore, the correlation between the shape of the vortex and the wind noise level measured in the passenger compartment is investigated.