【摘要】 孔腔流动与流激噪声是流声耦合研究领域的重要课题。文章基于大涡模拟方法与Kirchhoff积分,探讨了水中孔腔流动的发声机理。由孔腔流动振荡模态分析可知,在水中较低马赫数情况下,流体共振模态极难存在,故而流体动力振荡是产生孔腔流激噪声的根源,从而揭示了孔腔流激噪声形成的机理。进而又基于Kirchhoff控制面积分与物体壁面积分,辨识了偶极子声源和四极子声源对于流激噪声影响量级以及频谱分布规律,并结合流体动力声源的数学表达、Lighthill应力张量的频谱分析和壁面效应分析,指出了孔腔中涡旋对于流场脉动量声学效应的输运作用是孔腔流激噪声传播的成因,从而揭示了孔腔流激噪声传播的机理。更多还原

【Abstract】 Cavity flow and flow induced noise are two important issues in the field of flow-acoustic coupling.The mechanism of cavity flow induced noise in water is studied by the large eddy simulation(LES) and Kirchhoff integral in this paper.The cavity flow oscillation analysis shows that the fluid-resonance mode is impossible in the condition of low Mach number in water,and the fluid-dynamic oscillation determines the generation of cavity flow induced noise.After that,the effects of dipole and quadrupole sources on the acoustic spectrum are identified according to Kirchhoff control surface integral and body surface integral.With the analysis of mathematical expression of acoustic source,the power spectrum of Lighthill stress tensor and wall influence,the radiation of flow induced noise should be attributed to the vortex transportation of the acoustic effect in fluctuations of unsteady flow.更多还原