Propagation of guided waves in a non-uniform acoustic waveguide

Jean-François Mercier , Agnes Maurel

We study the time harmonic propagation of acoustic waves in a waveguide with varying cross section. This is done using a multimodal approach. The modal components are expressed thanks to an integral representation (Lipmann Schwinger representation) that is used to iterate the Born approximation. We compare the classical approach in which the infinite sum of modes is truncated in the practice to a new formalism in which the sum of modes is finite and an extra mode is artificially added. This method has been shown to ensure a better convergence because the additional mode allows a better approximation of the boundary condition at the walls. Numerical calculations are proposed and compared to direct finite element simulations to validate the iterated Born approximation. Analytical solutions are proposed in the first Born approximation and compared to classical results for the low frequency regime.

Mots clés: guided waves; scattering of sound; modal method; born approximation

Domaines: Acoustique [physics.class-ph]

Jean-François Mercier, Agnes Maurel. Propagation of guided waves in a non-uniform acoustic waveguide. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810835⟩