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 which neglected flow induced coupling between the structural modes. Yet, flow induced modal 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 which demonstrate the effect that such coupling has on the sound power radiated from a plate.
Numerical simulation of acoustic radiation from vibrating plates with slits.