Study on Stability Standards of ship

综述了国内外船舶在横浪条件下的稳性标准。紧急状态船舶在四分一海浪中倾覆前的稳性标准调查。对一艘被拖曳的船模在剧烈的四分波作用下的侧向力和横摆力矩进行了分析和试验研究。为了研究船舶在极低遇遇频率下垂荡和纵摇运动时的侧向力，进行了大量的模型试验。将侧向力分为Froude-Krylov力、绕射力和升力，并进行了详细的讨论。在考虑淹没面积变化的情况下，研究了垂荡和纵摇运动对船舶侧向力的影响，并与模型上的实验确定的力进行了比较和理论预测。借助于数值模拟程序，指出了船舶在大浪中发生倾覆的临界情况。讨论了几个参数对临界情况的影响，以探讨倾覆的可能原因。此外，为了简化仿真程序，本文还用实用公式计算了作用在大变幅船体上的Froude-Krylov力。

Stability standards of domestic and international regulation are reviewed for ships in beam sea condition. Critical situations leasing up to capsizing of a ship in following quartering seas an investigated for stability standard. An analytical and experimental study of the side force and yaw moment on a ship model towed in severe quartering waves has been conducted. In order to investigate the side force on the ship with heave and pitch motions in a very low encounter frequency, extensive model tests have been carried out. The side force is divided into Froude-Krylov force, diffraction force and lift, and discussed in detail. The effects of heave and pitch motions to side force on the ship are investigated by taking into account the change of submerged sectional area Comparisons of the experimentally determined force on the model and a theoretical prediction are presented. Critical situations le ading up to capsize are pointed out for a ship in severe following and quartering seas by using the aid of numerical simulation program. The effect of several parameters on the critical situation is discussed to investigate the possible causes of capsizing. In addition, Froude-Krylov forces acting on a ship with large amplitude displacement are evaluated in the practical formulas to make simulation program simple.