同向双涡合并过程声波研究

Acoustic wave in two corotating vortices pairing

为了对常见不稳定流中声波产生过程的基本物理现象进行研究,基于大涡模拟方法与高阶精度加权本质无振荡混合格式,对剪切流中同向双涡合并过程的动力学流场及其声场进行了数值模拟。结果描述了同向旋转双涡合并过程,揭示了双涡合并产生旋转四极子声源的机理,且与相关研究相符。对剪切层的气动声场进行了数值模拟,揭示了剪切层中双涡旋转合并过程,发现涡合并过程产生的声波在整个剪切层声场中占主导作用,且合并在半个周期内完成。

To investigate the basic physics of acoustic wave generation in common unsteady flows,the dynamics flow and acoustic field produced by the coalescing of two corotating vortices in the shear flow are simulated based on the high order hybrid weight essentially non-oscillatory( WENO) scheme and large-eddy simulation( LES). The results reveal the pairing process of two corotating vortices,and show the generating mechanism of the rotating quadrupole source during vortex pairing. The numerical results agree well with the previous investigations. The acoustic field of a mixing layer is simulated,and the vortex pairing process of the mixing layer is shown. The results show that the acoustic wave generated by the vortex pairing dominates the whole acoustic field of the shear layer,and the pairing process completes during one half cycle.