Finite element approach for three-dimensional linearized potential equation with application to muffler acoustic attenuation prediction

Abstract

In this paper, a three-dimensional finite element method for solving the linearized potential equation (LPE) is implemented to predict the acoustic attenuation performance of mufflers in the presence of nonuniform flow. For accurate physical representations, the porous material is modeled as equivalent fluid with complex speed of sound and density while the background mean flow in fluid domain is captured by solving Reynolds-averaged Navier–Stokes equations. The treatment details for boundary integrals at different boundary conditions and expressions for transmission loss are presented. Good agreements of predicted and measured transmission loss of two reactive and a hybrid mufflers validated the present approach. Finally, the convective effect of nonuniform flow on the acoustic attenuation behavior of the hybrid muffler is examined numerically in detail.