Analysis of Exhaust Elements Using the Transfer Matrix Method

Exhaust noise must comply with legislation requirements and meet customer expectations and cost reduction, which call for design optimisation of the exhaust systems in the development process. One solution is to calculate the transfer matrix of the silencer using 3D linear pressure acoustics in a FEM software. The transfer matrix is the basis for calculating either the insertion loss or transmission loss of a silencer. The simulations of different silencer configurations are verified with measurements in a flow acoustic test rig using the two source method, and this test setup is, without modifications, also used for extracting the complex wave number and impedance of isotropic absorptive material, which are used to update the FE models.