Finite element method for prediction of acoustic attenuation performance of silencers with three-dimensional potential flow

摘要

Finite element method is developed to predict and analyze the acoustic attenuation performancernof silencers with complex three-dimensional potential flow. The three-dimensional convectedrnwave equation is derived first, and then the finite element formulations based on the Galerkinrnweighted residual method are established and the numerical procedure for prediction of acousticrnattenuation performance of silencers is presented. Compared to the conventional acoustic finiternelement method, the present approach takes into account the second order terms of mean flowrnMach number in the acoustic governing equation, so it is suitable for the acoustic analysis ofrnsilencers with higher Mach number subsonic flow. The four-pole parameters of a straight ductrnare calculated and compared with the one-dimensional analytical solutions to demonstrate therncomputational accuracy of the present approach. The finite element method is then used tornpredict the transmission loss of double expansion chamber silencers with inter-connecting tubes.rnThe numerical predictions showed that the influence of three-dimensional potential flow on thernacoustic attenuation performance of the silencers is worthy to be considered.