Abstract
In this work, the acoustic attenuation of a perforated muffler is numerically determined, in harmonic time regime and in absence of fluid flow, for the bidimensional case. We suppose that the hole diameter and the center- to-center distance between consecutive holes are of the same order epsilon. The formulation is derived from multiple scale technique and matched asymptotic expansions. The numerical method couples finite elements in the muffler with modal decomposition in the inlet and outlet ducts.