Validation of the reciprocal work identity method with AML for large silencer analysis

Large silencers usually involve many higher-order modes at the inlet and outlet. Traditional methods for evaluating the transmission loss (TL) have their limits on how to define the true anechoic termination. In this paper, the TL of large silencers is computed by two different numerical methods. The first method is the reciprocal work identity method when used in conjunction with the direct mixed-body boundary element method (BEM). The second one is to apply the Automatically Matched Layer (AML) boundary condition in the finite element method (FEM) of Virtual. Lab to calculate the insertion loss (IL). Results from both methods are compared to each other on several test cases with circular and rectangular cross sections.