船舶浅水操纵性能的数值仿真

Numerical simulation on ships maneuverability in shallow water

采用深水MMG船舶操纵运动方程,对其中各水动力导数进行浅水修正,建立了浅水操纵运动数学模型。采用四阶龙格库塔法求解,用MATLAB语言编制了相应计算程序,并对三峡水利工程枢纽通航船队浅水操纵性进行了模拟仿真处理。通过与已有文献试验结果的对比,证明了数值模拟的准确性。通过对浅水中船队回转性和航向稳定性的模拟仿真,研究了浅水对回转性和航向稳定性的影响。发现船队在浅水区域运动,在同样舵角下定常回转圆的直径增大;在同样的回转圆直径下,漂角减小,速度降减小。通过对船队在浅水中Z形运动性能预报,模拟计算的K、T指数与试验结果进行了对比,吻合较好。浅水较深水初转期时间增加,超越角减小,说明船队航向稳定性有所提高,相应舵力变小。

Hydrodynamic coefficients are corrected for shallow water, and shallow water maneuverability equations are established by using MMG ship maneuverability equations. The equations are computed by using fourth-order Runge-Kutta method. MATLAB language is adopted to make calculation program, Simulation processing is given for Three Gorges Project fleet of ships of shallow water navigation by using MATLAB software. The accuracy of shallow water maneuverability equations are verified by comparing the simulation result with the experimental results in literatures. Turning ability and shipping-direction stability of fleet in shallow water are simulated, the effect of shallow water is studied. It is found that constant turning circle diameter of flee increases with the same rudder angle in shallow water, the drift angle decreases with the same turning circle diameter. Z shape motion performance of fleet for shallow water is forecasted,the simulated K, T are in agreement with experimental data. The shipping-direction stability of shallow water increases compared to deep water.