一种基于有限元/边界元耦合方法的管道进口声传播及声辐射模型

本文发展了一种基于有限元和边界元耦合方法的管道进口声传播及声辐射计算模型。该模型将整个声场分为内部有限域和外部无界域，分别用有限元和边界元方法求解控制方程，在二者之间的界面上使用具有物理意义的声阻抗参数进行匹配，并通过一种快速迭代方法实现全声场求解。这种迭代方法可以保证有限元刚度矩阵等带宽以及对称的特性不被破坏，有助于提高计算效率。该模型先得到了Levine and Schwinger标准解的检验，进而在无流动情况下对于简化的航发短舱进口管道模型进行了噪声辐射现象的数值模拟，最后基于计算结果分析了声衬对远场声辐射的影响。

A FEM /BEM Combined Model for the Prediction of Sound Propagation and Radiation of a Duct Inlet

A finite element/boundary element combined method is developed that uses the FEM to solve the acoustic transmission of inner acoustic field inside the duct, while employing the BEM to construct the artificial boundary condition for the far field radiation computation. The FEM and BEM are matched by the impedance continuity condition at the interface between the computational domains, and the combined numerical code is solved by a fast iteration algorithm. A validation of the model is first carried out by comparing the present results with the Levine-Schwinger solution for the sound radiation of a cylindrical pipe opening. Furthermore, the present model is used to simulate the sound propagation and radiation phenomenon for a simplified duct configuration of an aeroengine nacelle when there is no flow being present. Finally, an analysis is done of the acoustic liner effect on the far field sound radiation based on the simulation results.