Sound Radiation From a Flow-Excited Rectangular Plate With Visco-Elastic Supports

Abstract

In road vehicles, one dominant “wind noise” generating mechanism is the flow-induced vibration of side-glass windows. Side-glass windows are excited by unsteady surface pressures associated with turbulent flows over the vehicle body. In this study, experiments were performed in order to investigate the sound radiated by a seal-supported, rectangular aluminum panel excited by separated/reattached flow. The primary goal of this investigation was to assess the influence of seal mechanical properties and geometries on the sound transmission loss of the side-glass window. Experimental modal analysis test was conducted to accurately measure the resonance frequencies and the modal damping ratios of the panel. Surface pressure measurements were performed using small-diameter condenser microphones. The influence of the excitation spectrum on the radiated noise level was determined. The results were compared with theoretical predictions obtained using an analytical model based on a variational formulation of the problem. The flow-excited vibration response was predicted accurately for two different turbulent flows. The vibration energy dissipation at the sealing system reduced the amplitude of the plate vibration at resonance and the radiated sound.