Propagation et rayonnement acoustique en présence d'un écoulement non uniforme par une méthode de couplage FEM/BEM

Abstract

ABSTRACT To take in to account the effects of non-uniform mean flow, we have developed the linear acoustic equation in terms of acoustic velocity potential when the mean flow in potential. This equation is obtained by linearisation of Euler's equations. For non-potential mean flow, we developed the linear acoustic equation in terms of lagrangian perturbed displacement written in Eulerian variables in association with mean flow: (mixed formulation or Galbrun equation). The first equation is associated with the continuity of normal component of velocity at the interface discontinuity and the second equation is associated with the continuity of normal component of lagrangian acoustical displacement. For solving these equations, we couple the two numerical methods: Finite Element Method (FEM) and Boundary Element Method (BEM). The first is used in bounded domain where the mean flow is non- uniform, and the second is used for unbounded domain without flow.