The effect of flow-induced coupling on sound radiation from convected fluid loaded plates

Abstract

Recent investigations concerning the effects of fluid convection on structural acoustic radiation have noted that radiation efficiency increases with increasing flow speeds. However, most of these studies based this conclusion on simulations that neglected flow-induced structural mode coupling. Yet, flow-induced coupling is know to have dramatic effects on structural dynamics including static and dynamic instabilities, and should therefore be expected to significantly affect sound radiation. The purpose of this investigation is to quantify the effects that fluid flow has on the sound radiated from rectangular vibrating plates when flow-induced structural modal coupling is considered. The discussion includes a description of the fundamental physics associated with a simply supported, vibrating, rectangular plate imbedded in an infinite baffle and radiating into a semi-infinite, convected fluid. This is followed by a discussion of the effect that flow-induced coupling has on the structural dynamic behavior. Finally, numerical results are presented that demonstrate the effect that such coupling has on the sound power radiated from a plate.