Transparent boundary condition for acoustic propagation in duct with bulk-reacting liner

International audienceThe proposed study focuses on the modeling of acoustic wave propagation in infinite guides lined with bulk-reacting sound absorbing material which allows acoustic propagation through the lining. The finite element method is used, it is then necessary to limit the numerical domain by an artificial boundary on which a transparent boundary condition is introduced. The method described in this work consist to write the transparent condition as a Dirichlet to Neumann operator (DTN) based on a modal decomposition of the pressure in the guide. This study is a generalization of recent works with absorbent materials modeled with impedances boundary condition. The presented method can be useful for the acoustic design of silencers, air-conditioning ducts, industrial fans, and other similar applications