波浪中回转船舶横摇运动研究

Study on Rolling Motions of a Ship Turning in Regular Waves

基于经典MMG分离式模型,结合三自由度船舶平面运动与横摇、纵摇、垂荡运动的耦合,建立了波浪中船舶六自由度操纵耐波全运动模态的数学模型。船体力、桨力及舵力采用经验公式估算。波浪力建模中,采用三维面元法计算不同浪向下六自由度一阶频域波浪力及二阶波浪漂移力,并利用卡明斯脉冲响应,在计入时间效应的前提下,将频域的阻尼系数和绕射波浪力分别转化为时域内的辐射和绕射力。应用该模型对S175集装箱船在不同波浪条件下进行了数值模拟,并与耐波性试验和自航模试验结果进行了比较,初步验证了该波浪力模型和运动模型计算程序的有效性。在此基础上分析了不同波浪条件和其他影响参数对回转船舶横摇运动的影响。认为波浪条件(波幅、波高、初始浪向角)、横摇阻尼、初稳性高对回转横摇运动影响显著。

This paper presents a mathematical model which combines traditional 3 degrees of freedom（3-DOF） MMG model and sea-keeping motions with roll, pitch and heave to simulate the ship maneuvering motions coupling with sea-keeping motions in different waves. Hydrodynamic derivatives, propeller and rudder forces are estimated by empirical formulas using basic ship parameters. As for wave forces, the first order ones are evaluated in time-domain by using Cummins impulse response function; the second order ones are solely taking its mean average part into account. Further more, the 6-DOF model is employed to simulate maneuvering and seakeeping motions of a container ship S175 simultaneously. A code of this model is developed. It is verified by the measured data obtained from seakeeping tests and free running model tests. Then Roll response to various wave conditions and other factors are investigated. The results show that wave conditions, roll damping and GM have significant impact on the turning roll motion.