ONR内倾船在波浪中船桨舵耦合下航向保持数值模拟

Numerical Simulations of ONRT Coupled with Propellers and Rudders in Waves under Course Keeping Control

波浪中船舶航向保持能力反映了船舶操纵性能的优劣。论文使用通用的商业软件STAR-CCM+,模拟ONR内倾船在顶浪和艏斜浪下的航向保持性能。采用重叠网格技术,实现船桨舵耦合的多体运动求解。通过速度边界条件进行造波,采用欧拉叠加模型结合势流方法进行消波,并对舵施加自动控制来实现航向的保持。通过计算给出了船舶在顶浪和艏斜浪中的六自由度运动参数和舵角变化的时历曲线,并与2015年东京CFD Workshop中公开的模型试验数据进行了对比分析,相关结果与试验吻合较好,验证了论文提出的波浪中船舶航向保持计算方法的可靠性。还分析了自航船舶在一个波浪遭遇周期内顶浪和艏斜浪中自由面和尾流场涡结构的变化。

Capability of course keeping in waves reflects the performance of ship maneuvering. Course keeping of a free running ship in waves involves ship-propellers-rudders coupling control technology, which is the fundament of the simulation for failure of extreme motion of the ship. In this paper, the numerical investigation of a free running ship in heading and bow quartering waves is carried out using commercial CFD solver STAR-CCM+. Complex ship motions with actual rotating propellers and moving rudders are calculated using dynamic overset grids. Waves are generated by the velocity boundary;the Euler overlap method is adopted for wave absorbing. Furthermore, the rudder control is developed to simulate free running ship under course keeping. Prediction of ship motions and the rudder deflection are compared with the available experimental data from Tokyo 2015 CFD Workshop. Good agreements are achieved and show that the present approach is suitable for the numerical simulation of free running ship under course keeping control in waves. In addition, free surface elevation and stern vortex are presented in heading and bow quartering waves in one encounter period.