Acoustic Wave in a Uniform Flow

Abstract

This chapter presents the governing equations for acoustic waves in a viscous fluid. Introducing a small parameter, the nonlinear field equations are linearized and reduced to a single partial differential equation for velocity potential or pressure deviation. The Green's function which shows the acoustic field in a uniform flow is derived by the method of integral transform. The convolution integral for the inversion transform is demonstrated to obtain the time-harmonic response. An application technique of the complex integral is also demonstrated in order to transform an infinite integral along the complex line to that along the real axis in the complex plane. It enabled us to apply the tabulated integration formula.