浅海分层波导内弹性结构声辐射等效源计算方法
A method for solving the equivalent sources of acoustic radiation from elastic structures in shallow-water layered waveguide
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摘要: 针对计算浅海波导内弹性结构等效源时涉及到大量近距离、大陡度下格林函数计算问题, 本文提出了一种基于离散复镜像法的浅海分层海底波导中近距离低频格林函数高精度求解方法。该方法基于波数积分的严格形式, 通过对分层海底界面反射系数进行指数函数拟合, 可计算海底界面引入的各种波成分, 从而获得高精度的格林函数。使用该方法计算了浅海等声速海水介质和弹性海底、单层低声速沉积层以及多层沉积层海底条件下的格林函数, 开展了波导内靠近海底处点激励弹性球壳的等效源法辐射声预报研究, 研究结果表明, 使用本文方法计算格林函数可实现高精度的弹性结构辐射声场预报。Abstract: Aiming at the problem of calculating the equivalent sources of elastic structures in shallow water waveguide, which involves a large number of near-field Green’s function calculations at close range and large steepness, this paper proposes a high-precision method to calculate the Green’s function in the near-field based on the discrete complex image method. The method is based on a strict form of wave number integration, which fitting a list of exponential functions to the reflection coefficients of the layered seabed, and allows the calculation of all the wave components. The method was used to calculate the Green’s function of the waveguides with constant sound speed water media and the elastic seabed or the single/multilayer sedimentary seabed, and the prediction of the radiation sound field of a spherical shell close to the seabed in the shallowwater waveguide of the three typical seabed is carried out, and the prediction results match well with the finite element results. The results show that the Green’s function calculated by this method can realize high-precision radiation acoustic field prediction of elastic structures.
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