The wind-noise-level in the cabin of a vehicle depends on the magnitude of the aerodynamically generated noise and noise isolation characteristics. Therefore, one good way to reduce the wind-noise-level in the cabin is to minimise the acoustic noise itself generated by the turbulent air flow around the vehicle at high speed cruising.
This paper describes the relation between the turbulent flow and the aerodynamic noise as well as how to estimate the magnitude of aerodynamic noise, especially around A-pillar of a production vehicle.
First, the flow visualization and the detailed measurements of flow clarify the vortex structure generated around A-pillar and side window.
Secondly, sound pressure fluctuations measured on the side window surface are discussed in relation to the vortex structure.
Lastly, in order to estimate the order of the magnitude of aerodynamic noise we, propose physical parameters given by approximating the solution of Lighthill's equation.