The sound wave equation in potential flow was derived, and its weak form of finite element method (FEM) was established by means of Galerkin weighted residual method. For the calculation of pipe acoustic problems, the treatment method of boundary conditions was given, and the finite element matrix equation was obtained with discretization and assembly. The acoustic attenuation characteristics of Herschel-Quincke (H-Q) tube was calculated and analyzed using the finite element code written by authors. The results showed that in middle and low frequency bands, the FE calculation results are in good agreement with one-dimensional theoretical calculation ones to verify the correctness of the proposed method; in higher frequency band, the obvious difference between the two is mainly due to 3-D wave and 3-D flow effects at the junction of main pipe and branch pipe; medium flow affects anechoic characteristics of H-Q tube, especially, the resonance frequency and the passing frequency are affected more significantly with increase in Mach number; the variation of structure form can greatly improve the noise elimination performance within a specific frequency range.
Key words
wake sound field /
finite element method (FEM) /
Herschel-Quincke tube /
anechoic characteristics
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References
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