Based on the previous study of the numerical method for aerodynamic noise computation under low Mach number, a hybrid method of large eddy simulation (LES) and Lighthill's acoustic analogy theory is established to compute hydrodynamic noise. The experiment data of the underwater jet noise in literatures is used to validate the proposed hybrid method. First of all, a three-dimensional model for underwater jet noise analysis is built according to the size of the experimental model, and the structure meshes for the calculations of flow field and the acoustic field are prepared. The computational domain size is determined by trial method. Then, the jet flow field is simulated by LES. According to the pressure difference, pressure pulsation and velocity inhomogeneity, the characteristic of the turbulence flow field and the stability of computation are analyzed. Afterwards, the necessary acoustic quantities at the nodes of the acoustic mesh are provided by interpolation of the flow field results. The underwater jet noise is simulated based on Lighthill's acoustic analogy theory. Finally, the solutions obtained by the hybrid method are compared with the experimental data of the underwater jet noise. The correctness and feasibility of the hybrid method are verified. Results show that the hybrid method of LES and Lighthill's acoustic analogy theory is able to simulate the underwater jet noise and hydrodynamic noise.%在前期对低马赫数下气动噪声计算方法的研究基础上,建立大涡模拟(LES)和Lighthil声类比水动力噪声混合计算方法,并通过参考文献中的水下射流声学实验结果对该方法进行验证.首先,参考试验模型尺寸建立三维模型,分别划分流场计算和声学计算所需结构网格,通过试算确定外流域大小和网格划分方式;接着,采用LES对射流流场进行计算,通过压差、压力脉动、速度不均匀度等指标对湍流流场特性和计算稳定性进行分析;随后,将流场计算结果作为声源项插值到声学网格,基于Lighthill声类比理论,对水下射流噪声进行计算;最后,对比水下射流声学试验数据与流噪声计算结果,验证和分析该混合计算方法计算水下射流噪声的可行性和正确性.结果表明,所建立的LES和Lighthill混合计算方法能较好地模拟水下射流噪声,可用于水动力噪声的研究.
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