Abstract: In order to investigate the effect of gas flow on transmission loss (TL )， the finite element method (FEM) was used in conjunction with the computational fluid dynamics (CFD) to solve the problem of flow-sound coupling. The TL of the straight-through perforated pipe silencer was calculated using the CFD/FEM approach in the presence of gas flow， whose results were compared with the experimental data and predictions from the literature so as to validate the accuracy of the present study. It was concluded that with the increase of flow velocity ， the TL decreases remarkably at the resonance peak and increases at most frequencies， especially at the higher frequencies when the turbulence noise induced by gas flow is neglected， and with the increase of gas temperature， the TL curve shifts to higher frequencies.

Key words: straight-through perforated pipe silencer, transmission loss (TL), gas flow, finite element method (FEM), computational fluid dynamics (CFD)