气动声学数值模拟中无反射边界处理及声源模型的建立

NonReflective Boundary Conditions and Sound Source Modeling in Computational Aeroacoustics

运用特征分析和事后修正法对无反射边界进行了分析，将两种常用的无反射边界方法（Ｔｈｏｍｐｓｏｎ无反射边界和Ｇｉｌｅｓ无反射边界）以统一的形式表达出来，得到这类边界的事后修正式．运用同一方法讨论了声能量从边界输入时声源的模化问题，给出单极源的边界声源数学模型．计算了单极源在均匀流中的声辐射．结果表明，文中方法计算准确，程序编制方便，适合于小振幅波动方程的计算．

The common NonReflective Boundary Conditions (NRBCs), such as Thompson's and Giles', are often complicated to program. In this paper, a new method to deal with NRBC is developed based on the characteristic analysis and subsequent correction. By this method the existing NRBCs are unified formally and it is easier to program these NRBCs. The same method is used to model sound sources when sound is emitted from boundaries and the aftercorrection equation for a monopole source is given. As an example, the sound radiation in a compressible stream is calculated to validate the present method. The result reveals that the developing method is convenient and accurate for NRBC and sound source modeling. It can be directly extended to cope with other kinds of sound source such as dipoles and quadruples. 