Numerical Simulations for Highly Nonlinear Behavior of a Ship in Large-Amplitude Waves

(1)开发了模拟气、液、固多相流的数值计算程序。该程序基于CIP-CUP方法，具有数值扩散少、可同时求解可压缩流体和不可压缩流体的特点。波浪冲击问题被研究作为程序的检查，我们发现程序非常通用，即使是断路器和飞溅发生。(2)对大振幅孤子波作用在静水上平台上的脉冲压力和合力进行了数值计算与实验对比。不仅在这种情况下，而且在l型结构甲板上的绿水与甲板上的反射波之间复杂的相互作用之间也得到了很好的一致性。(3)建立数值波槽，安装柱塞式或襟翼式造波器，设置数值吸波滩，防止波浪反射。然后在数值波槽中对浮体在大波作用下的非线性运动进行了数值模拟。验证了漂移力和脉冲波浪力的计算成功，计算方法通用性强。(4)采用三维时域格林函数法，研究了所谓的体非线性计算方法。对艏部有信号弹的实际船舶，成功地预测了波浪诱导运动和附加阻力，结果与实验结果吻合较好。

(1) A numerical calculation program was developed for simulating the multi-phase flow with gas, liquid and solid. This program is based on the CIP-CUP method, which is featured in less numerical diffusion and being capable of solving the compressible and incompressible fluids simultaneously with the same equations. The wave impact problem was studied as a check of the program and we found the program very versatile even for the breaker and splash occurring.(2) Comparison between numerical results and corresponding experiments was made for the impulsive pressure and resultant force acting on a platform fixed above the still water due to a large-amplitude soliton wave. Good agreement was confirmed not only for this case but also for complicated interactions between the green water coming onto the deck of a L-shaped structure and the reflected waves on the deck.(3) A numerical wave tank was established, with a plunger-type or flap-type wavemaker installed and the numerical absorbing beach to prevent the wave reflection. Then numerical simulations were performed in this numerical wave tank for the nonlinear motions of a floating body caused by large-amplitude waves. It was confirmed that the drift force and impulsive wave force were successfully computed and the computations were very versatile.(4) By means of the 3-D time-domain Green function method, the so-called body nonlinear calculation method was studied. The wave-induced motion and the added resistance in waves were successfully predicted even for an actual ship with flare near the bow, which was found to be in good agreement with experiments.