Acoustic edge scattering by a heavily loaded elastic half-plane

Abstract

The interaction between a compact turbulent eddy and a thin elastic half-plane, immersed in an otherwise stationary acoustic medium, is examined in the limit when fluid-plate coupling effects are large. The eddy is assumed to be close to the surface of the elastic plate but many acoustic wavelengths from the edge. Energy is transferred from the vicinity of the eddy to the edge of the plate in a non-attenuating coupled wave mode, producing a scattered sound field whose intensity is substantially greater than that radiated by the eddy in free space. When the elastic half-plane is freely joined to a semi-infinite rigid baffle, the increase on intensity is proportiosal to M ‒9/5 ( M is the eddy Mach number) and the sound field exhibits the directional characteristics typical of the field radiated by an edge scattering half-plane. In the absence of the rigid baffle, however, the sound field is less strongly directional and the increase on intensity is proportional to M ‒2/5 .