An acoustic intensity analysis system based on boundary element method and its applications.

Abstract

There is an increasing need for research and development to reduce the noise from vibrating bodies. In recent years the acoustic intensity (AI) has been attracting attention in this field. The AI is a time-averaged vectoral value of the product of sound pressure and particle velocity, and hence it can be used to visualize an acoustic field and also to identify the noise source. It is reported that the complex AI is more suitable for such purposes. This paper is concerned with development of an AI analysis system by means of the boundary element method.The Helmholtz equation is assumed to hold for the acoustic field under consideration. The corresponding integral equation is used to obtain an integral equation expression of the AI. The resulting expression is discretized by means of the usual boundary element method, from which one can compute the AI at any internal points in the acoustic field. The analysis system is applied to several example problems and the results obtained are discussed, whereby the usefulness of the system developed is demonstrated.