中文摘要：

陷落腔结构作为船舶表面的一种常见结构，其产生的噪声近年来广受关注。文章在马赫数为0．0048条件下，采用LES-Lghthill等效声源法对刚性壁面三维陷落腔的流场及声场进行仿真，形象地再现了陷落腔内部涡旋运动变化规律，分析了陷落腔涡流流动机制、脉动压力特性以及辐射噪声特征。通过对脉动压力功率谱及声功率频谱的对比分析发现，声功率谱的前三阶频率与陷落腔流体动力振荡频率吻合，这表明刚性壁面的三维陷落腔涡流噪声由流体动力振荡引起，由脉动压力构成的偶极子源对涡流噪声的贡献最大。研究成果为控制船舶涡流噪声提供了理论依据。

英文摘要：

Turbulent flow noise generated by the 3D rigid cavity has attracted an increasing amount of attention during the past decade. In this paper, the flow field and the turbulent flow noise generated by the flow past 3D rigid cavity at Mach number 0.004 8 was simulated by LES-Lighthill equivalent sources method.The turbulence motion inside the cavity and the characteristics of the radiated noise are described vividly. By comparing the mechanism of turbulence, wall pressure fluctuations, characteristics of the radiated noise, the relationship between vortex and sound is revealed. It is found that the first three frequen- cies in the sound power spectrum agree with the frequencies of hydrodynamic oscillation.It is indicated that the turbulent flow noise of 3D rigid cavity is induced by the oscillation of the fluid, and the dipole source, which is constituted by the wall pressure fluctuations, makes the largest contribution to the turbulent flow noise.Achievement of this paper provides a theoretical basis for controlling the turbulent flow noise of underwater vehicle.