The radiation sound field of a rectangular panel set in an infinite wall and excited by a turbulent boundary layer

Abstract

A flexible panel, set in the an infinite wall, is subject to an excitation force distribution which can be described by a correlation function. The panel vibrates and radiates sound. Expressions are derived for the intensity and pressure power.spectrum in the sound field at points which are far away from the panel in comparison with the superficial dimensions of the panel. If the excitation of the panel is due to the flow, over one of its faces, of a turbulent boundary layer, the thickness of which is small in comparison with the superficial dimensions of the panel, then an approximate expression for the correlation function of the excitation force distribution can be used in the evaluation of the expressions obtained. This evaluation has been made to determine the intensity and pressure power spectrum at points on or near to the normal through the centre of the undisturbed panel and on the other side of the panel from the one containing the boundary-layer flow. In this way we can determine the way in which the intensity and pressure power spectrum at these points depends on the plate dimensions and material properties, on the speed of the flow containing the boundary layer, on the thickness of the boundary layer and on the density of and speed of sound in the fluid medium around the panel.