Acoustic attenuation analysis of perforated tube dissipative silencers with offset extended inlet/outlet

摘要

The two-dimensional finite element method is used to calculate the transversal modes of perforated tube dissipative silencer with offset extended inlet/outlet, and the numerical mode matching method is developed to determine the acoustic attenuation performance. The corresponding formulation is derived and the computational code is written. For a circular concentric configuration, the transmission loss results from the numerical mode matching method, the three-dimensional finite element method and experiment agree well, which validated the accuracy of numerical mode matching method in predicting the acoustic attenuation performance of perforated dissipative tube silencer. The numerical mode matching method is then used to investigate the effects of offset of perforated tube, density of porous material and extensions of inlet and outlet on the acoustic attenuation performance of the elliptical perforated tube dissipative silencer.