The appropriate radiation conditions of ship motion problem with advancing speed in frequency domain are investigated from a theoretical and practical point of view. From extensive numerical experiments that have been conducted for evaluation of the relevant radiation conditions, a hybrid radiation technique is proposed in which the Sommerfeld radiation condition and the free surface damping are mixed. Based on the comparison with the results of the translating and pulsating Green function method, the optimal damping factor of the hybrid radiation technique is selected, and the observed limitations of the proposed hybrid radiation technique are discussed, along with its accuracy obtained from the numerical solutions. Comparative studies of the forward-speed seakeeping prediction methods available confirm that the results of applying the hybrid radiation technique are relatively similar to those obtained from the translating and pulsating Green function method. This confirmation is made in comparisons with the results of solely applying either the free surface damping, or the Sommerfeld radiation condition. By applying the proposed hybrid radiation technique, the wave patterns, hydrodynamic coefficients, and motion responses of the Wigley III hull are finally calculated, and compared with those of model tests. It is found that, in comparison with the model test results, the three-dimensional Rankine source method adopting the proposed hybrid radiation technique is more robust in terms of accuracy and numerical stability, as well as in obtaining the forward speed seakeeping solution.

从理论和实践的角度研究了随频域推进的船舶运动问题的适当辐射条件。通过为评估相关辐射条件而进行的大量数值实验，提出了一种混合辐射技术，其中将Sommerfeld辐射条件和自由表面阻尼混合在一起。在与转换和脉冲格林函数方法的结果进行比较的基础上，选择了混合辐射技术的最佳阻尼系数，讨论了所提出的混合辐射技术的局限性，以及从数值解中获得的精度。 。可用的前向航海预测方法的比较研究证实，应用混合辐射技术的结果与从平移和脉动格林函数方法获得的结果相对相似。与仅应用自由表面阻尼或Sommerfeld辐射条件的结果进行比较，可以得出这一确认。通过应用所提出的混合辐射技术，最终计算出了Wigley III船体的波型，流体动力系数和运动响应，并将其与模型测试进行了比较。结果发现，与模型测试结果相比，采用本文提出的混合辐射技术的三维朗肯源方法在精度和数值稳定性方面更加稳健，