Sound pressure at the surface of a cylinder due to a point source

Abstract

The prediction of the sound pressure field at the surface of a cylinder is of interest in many fields of acoustics, especially for investigating the acoustic loads induced on the payload fairing during launch of a space vehicle. For the launch environment of a space vehicle, the source position and strength determine the external sound pressure excitations on the vehicle. Unfortunately, existing analytical derivations for the acoustic field around a cylindrical geometry are not able to consider the source position, and the source is typically assumed to be at an infinite distance from the cylinder. There is also no scope in these theories to consider the decay of the source strength due to wave propagation. Therefore, effort has been spent here to modify the existing theories to make them applicable to a finite distance between the source and the cylinder and to allow for the decay of the source strength due to wave propagation. The theory has been used to check the accuracy of the Boundary Element Method (BEM) for calculating acoustic loading at the surface of a cylinder. In addition, the analytical and numerical models have been verified experimentally with measurements of sound pressure patterns at the surface of a cylinder at various frequencies due to a point source positioned at a finite distance from the cylinder surface.