Numerical investigation on the contribution of underbody flow-induced noise on vehicle interior noise

Aerodynamic noise transmitted through greenhouse panels and sealing often dominates the higher frequencies of the interior noise level, whereas the underbody area contributes mainly to low and middle frequencies. A method that unsteady Computational Fluid Dynamics (CFD) for exterior airflow combined with Finite Element Method (FEM) for interior acoustic response was used. To validate the accuracy of this method, the interior wind noise of a simplified vehicle model proposed by Hyundai was computed. The comparison between the computational and experimental result showed that this method had enough accuracy to compute the interior wind noise induced by the exterior flow field. Then, the same method was used to compute the wind noise transmitted through the underbody of a passenger car. The characteristic of the noise source and noise inside the cabin was revealed, and the contribution of underbody flow-induced noise to the interior noise was also investigated. Finally, the influence of the underbody panels thicknesses on the interior wind noise was evaluated.