Homogenization of transmission conditions for analysis of acoustic waves in domains with perforated barriers

We consider structures like the muffler of the engine exhaust, where the acoustic waves propagate through periodically perforated barriers. Recently we proposed a homogenized model [6] of the acoustic transmission through the layer with embedded rigid obstacles of arbitrary shapes, which represent the perforation. The homogenized model describes relationship between jump of the acoustic pressures p⁺ and p⁻ at the discontinuity interface Γ₀ and the transverse acoustic velocity g^0±, on introducing in–layer acoustic pressure p⁰ which describes wave propagation along the interface. The coupling between the transversely and the tangential acoustic velocities may become important for certain types of perforations. A sensitivity study was done which reveals remarkable dependence of wave transmission losses on the geometry of the perforation. Examples of 3D perforation geometries were treated. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)