Flow Induced Interior Noise Prediction of a Passenger Car

Prediction of flow induced noise in the interior of a passenger car requires accurate representations of both fluctuating surface pressures across the exterior of the vehicle and efficient models of the vibro-acoustic transmission of these surface pressures to the driver’s ear. In this paper, aeroacoustic and vibro-acoustic methods are combined in order to perform an aero-vibro-acoustic analysis of a Mercedes-Benz A-class. The exterior aero-acoustic method consists of a time domain incompressible Detached Eddy Simulation (DES) and an acoustic wave equation. The method is extended in this paper to account for convection effects when modelling the exterior sound propagation. The interior vibro-acoustic model consists of a frequency domain Finite Element (FE) model of the side glass combined with a generalized Statistical Energy Analysis (SEA) model of the interior cabin. The method is extended in this paper to account for additional geometric details that affect the direct and reverberant fields within the cabin. The overall approach is presented and validated against vibro-acoustics tests and wind tunnel measurements for two separate mirror designs. The aero-vibro-acoustic method achieves very good results and accurately predicts the change in interior noise resulting from an exterior body design change.