Abstract: In 2020, the IMO issued Interim Guidelines on the Second-Generation Intact Stability Criteria for Ships. To support the implementation of these criteria in the shipbuilding industry, ship design software requires time domain numerical methods of parametric roll with varying levels of accuracy and computational efficiency. First, a time-domain parametric roll mathematical model coupling heave, roll, and pitch in three degrees of freedom is developed based on two-dimensional and three-dimensional hydrodynamic methods. Second, in the two-dimensional hydrodynamic method, time-domain heave and pitch motions are obtained using a frequency-to-time domain conversion method, while in the three-dimensional hydrodynamic method, the three-dimensional time-domain mixed-source method is employed to directly solve for heave and pitch motions in the time domain. Subsequently, the Froude-Krylov moments and hydrostatic moments in the roll direction are solved along the instantaneous wet surface. Finally, using the international standard C11 container ship model, the effects of heave and pitch motions obtained from frequency-domain solutions, time-domain average wet surface solutions, and time-domain instantaneous wet surface solutions on parametric roll are compared, and the results are compared with model test data. It is verified that the three-degree-of-freedom mathematical models based on two- and three-dimensional hydrodynamic methods can quantitatively predict the time-domain motion of parametric roll in head waves.

Key words: second-generation intact stability criteria, direct stability assessment, parametric roll, three-dimensional time-domain mixed-source method

摘要： IMO在2020年发布了船舶第二代完整稳性衡准暂行指南,为支撑该衡准在船舶工业界的落地应用,船舶软件需要不同精度和计算效率的参数横摇时域预报方法。首先,该文基于二维和三维水动力方法构建垂荡-横摇-纵摇三自由度耦合的参数横摇时域运动数学模型;其次,在二维水动力方法中利用频域转时域方法获得时域垂荡、纵摇运动,在三维水动力方法中采用三维时域混合源法直接时域求解垂荡、纵摇运动;然后,沿着瞬时湿表面求解横摇方向Froude-Krylov力矩和静水力矩;最后,采用国际标模C11集装箱船比较频域求解的垂荡及纵摇运动、时域平均湿表面求解的垂荡及纵摇运动、时域瞬时湿表面求解的垂荡及纵摇运动对参数横摇的影响,并和模型试验结果进行对比,验证了基于二维和三维水动力方法的三自由度数学模型,能够定量预报顶浪参数横摇的时域运动。

关键词: 第二代完整稳性衡准, 直接稳性评估, 参数横摇, 三维时域混合源法