伴流声场计算的有限元方法及其应用

推导了势流中的声波方程,并运用伽辽金加权余量法建立了相应的有限元(Finite Element Method,FEM)弱形式.对于管道声学问题的计算,给出了所需边界条件的处理方法,通过离散和装配得到有限元矩阵方程.使用自行编写的有限元程序计算分析了 Herschel-Quincke(H-Q)管的消声特性.结果表明,在中...

Finite element methodand its application in computation of wake sound field

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.