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A boundary element analysis for simple expansion silencers with mean flow

Abstract A numerical scheme for obtaining the acoustic performance of silencers with mean flow is developed in this study. The differential governing equation for sound propagation in a medium with uniform velocity is derived first and then is converted to a Helmholtz equation by Prandtl‐Glauert transformation. Therefore, the numerical implementation for an integral Helmholtz equation can be applied directly. The numerical results for simple expansion silencers with different mean flow velocities are computed and also compared with other research. The agreement is good. In addition, the silencers with intruding tubes are also analyzed and compared with the experimental measurements.