Aero-Vibro-Acoustic Wind Noise-Simulation Based on the Flow around a Car

Aim of the ongoing development of passenger cars is to predict the interior acoustics early in the development process. A significant noise component results from the flow phenomena in the area of the side window. Wind noise is a physical problem that involves the three complicated aspects each governed by different physics: The complex turbulent flow field in the wake of the a-pillar and the side mirror is characterized by velocity and pressure fluctuations. The flow field generates sound which is transmitted into the passenger cabin. In addition to that, it excites the structure, resulting in a radiation of structure-borne noise into the interior of the car. Therefore, the sound generation is governed by fluid dynamics of the air flow. The sound transmission through the structure due to vibrations is determined by structural mechanics of the body structure. The sound propagation inside the cabin is influenced by interior room acoustics.

In the present work, different CFD simulations of the exterior flow were conducted to investigate the sound generation due to external air turbulence. For this purpose, a simplified model of an automobile was used. Additionally vibro and aeroacoustic simulations were conducted to solve the other two parts of the problem and to gain insight into the sound transmission into the passenger cabin.