Sound Wave Propagation In A Two-dimensional Flexible Duct In The Presence Of An Inviscid Flow

Abstract

An investigation is made of the phase velocity of the sound wave propagating in a two-dimensional flexible duct that carries a uniform flow. The flexible duct considered herein is composed of two parallel, thin elastic plates. The outer surfaces of the duct are in contact with a stationary fluid medium and its inside contains a uniform fluid flow. An eigenvalue problem is formulated for a two-dimensional flexible duct by satisfying pertinent boundary conditions across the fluid-plate interfaces. The sound pressure inside the duct is a summation of partial wave pressures, each of which is associated with a wave mode having its own phase velocity.