Structure of Aerodynamic Noise Sources Generated in Production Vehicle

Abstract

Experiment has been performed to clarify the structure of aerodynamic noise sources generated in a production vehicle. The details of noise sources were measured from the outside and inside of vehicle by applying noise source identification techniques. The noise sources show high level in the regions of bonnet head, front underbody, side window and rear window. Moreover, the noise sources are dominated by that from underbody in the low frequency, and side window in the high frequency, respectively. The velocity dependency of aerodynamic noise was analyzed based on Lighthill-Curle analogy. As a result, it is found that the noise sources around vehicle are mainly dipole sources.