Abstract：The two-dimensional finite element method is used to calculate the transversal modes of perforated tube dissipative silencer, and the numerical mode matching method is developed to predict 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 demonstrated the accuracy of the 2-D finite element method in calculating the transversal modes and the numerical mode matching method in predicting the transmission loss of perforated tube dissipative silencer, respectively. The numerical mode matching method is then used to investigate the effects of hole diameter, porosity, density of the sound-absorbing material and offset of the perforated tube on the transversal modes and acoustic attenuation characteristics of the circular straight-through perforated tube dissipative silencer. The results showed that smaller hole diameter or higher porosity or bigger offset of perforated tube may lead to wider effective frequency range of plane wave domination, and better acoustic attenuation performance in the high-frequency range, but worse acoustic attenuation performance in middle-frequency range. Increasing the filling density of sound-absorbing material may improve the acoustic attenuation in the mid to high frequency range.
2014, Vol. 33 
