中文摘要：

针对舰船在低频域内考虑流固或声固耦合作用的振动与声辐射计算问题，探讨了流固耦合与声固耦合动力学方程的等效性条件及两者差异，同时指出流固耦合方程与声固耦合方程在水下辐射噪声计算中不可联立求解或关联求解，进而结合国内研究现况归纳出舰船水下辐射噪声四种数值计算方法。以某小水线面双体船（SWATH）为例，采用声功率作为评价标准，比较各类方法在建模难度、求解规模、计算精度和效率等方面的优劣。研究表明，四种数值算法的计算结果均能满足工程需要，但采用声固耦合分析模式计算低频域水下辐射噪声较流固祸合分析模式在计算精度上有一定程度的提高。推荐声固耦合分析模式的耦合间接边界元（IBEM）方法为舰船水下声辐射数值预报首选方法，可为国内舰船水下辐射噪声计算提供参考与建议。

英文摘要：

Aiming at calculation of radiation noise of a ship in low frequency, this paper discusses equivalent conditions for both vibro-acoustic coupling equations and fluid-structure interaction equations and their differences. Because these equations cannot be solved simultaneously, four numerical methods are put forward. A small water-plane area twin hull （SWATH） is taken as a computational example, in which the sound power is adopted as an evaluation criterion. It is shown that all the four methods can satisfy engineering demands, and computation accuracy can be increased by using the vibro-acoustic coupling model. The vibro-acoustic coupling IBEM method is recommended for prediction of ship＇s underwater noise.