SOUND GENERATED BY FLUID-STRUCTURE INTERACTIONS

A tutorial summary is given of the theory of aerodynamic sound with sp ecial reference to the generation of sound by flow interacting with ri gid and elastic structures. Lighthill's acoustic analogy and the theor y of vortex sound are discussed. Several applications of the theory ar e described that exemplify the considerable progress that has been mad e in the analytical treatment of flow generated sound at low Mach numb ers, including the use of the compact acoustic Green's function to est imate fluid-structure interaction noise when one or more pertinent sou rce dimensions are small compared to the acoustic wavelength. The need to take proper account of additional sources formed by vortex sheddin g during an interaction is emphasized, and illustrated by the example of blade-vortex interaction noise. The modification caused by surface compliance of the efficiency of sound production by an adjacent flow i s discussed by reference to simple analytical models involving vortex flow near the edge of an elastic plate, and over a surface inhomogenei ty on a large plate. (C) 1997 Published by Elsevier Science Ltd.