3D acoustic field analysis in mufflers using finite element method

This paper describes the 3D analysis of acoustic field in mufflers and its acoustic attenuation using FEM. In applying the FEM to the open rigion of the muffler, the finite rigion was set to the muffler exit and the hemi-infinite rigion was set combining with the finite rigion outwards. The finite elements were introduced to the finite rigion and the decay type infinite elements to the hemi-infinite rigion. This method was applied to a cavity type muffler and the results were compared with both obtained through the transfer matrix method and pure tone experiments. The frequency characteristics of the attenuation of the muffler calculated by this method showed good agreements with the experiment results.