Abstract
KEYWORDS- wind noise, passenger car, CFD, BEM, SEA
ABSTRACT – When the car drives at high speeds, wind noise becomes the main noise source and one of the major complains of the passenger car from auto consumers. According to the previous researches, wind noise containing both turbulent convection component and acoustic component can propagate into the vehicle interior cavity through both structure-borne and air-borne. In this study, taking the both components into consideration, a passenger car was analyzed and the interior wind noise could be predicted based on CFD (Computational Fluid Dynamics) and SEA (Statistic Energy Analysis) simulation. Firstly, the unsteady CFD solver was used to simulate the incompressible flow field around the car in motion and the pressure fluctuation data on the automotive body surface could be acquired. The car body area was divided into small areas. Then, for the turbulent convection component, a turbulent boundary layer mathematical model was used to extract the convection wavenumber, spatial correlation decay coefficients and pressure amplitude at each small area, while for the acoustic component, BEM (Boundary Element Method) was used to obtain the spatially averaged sound pressure response at each area. Finally a full vehicle SEA model was built and validated by PBNR (Power-Based Noise Reduction) test method so as to be used to predict the sound pressure level inside the car. This methodology can well predict the vehicle interior wind noise, especially for each component.