A multidomain boundary element solution for silencer and muffler performance prediction

The multidomain boundary element technique is used for the analysis of muffler problems in which the acoustic region consists of thin obstacles, such as extended inlet or outlet tubes and internal connecting tubes. In this technique, a muffler is first divided into several subdomains and then the well-known Helmholtz integral equation is applied to each subdomain. Continuity conditions of acoustic pressure and normal velocity are enforced at the interface between two neighboring subdomains. A set of simultaneous linear equations can then be constructed and solved for the boundary unknowns, as well as the interface variables. The boundary element solution is compared with a finite element solution. Excellent agreement between these two solutions is observed in producing the transmission loss curves for different muffler configurations.