Acoustic scattering in waveguides with smoothly-varying or discontinuous elastic boundaries

Abstract

A method for solving boundary-value problems where a boundary parameter varies continuously in space is applied to some canonical waveguide problems. The method, previously employed by Roseau and Evans, generates a functional difference equation, the solution to which enables fluid velocity potential to be written as an explicit integral transform. The two main problems to which the method is applied are a two-dimensional waveguide with a varying impedance condition and an elastic-walled waveguide with varying bending stiffness. Limiting versions of the two problems are solved using the Wiener-Hopf technique. This provides a check on the varying-parameter solutions as well as being of interest in itself.