随浪规则波中ONR内倾船纯稳性丧失黏流模拟方法研究

Study on Viscous Simulation Method of Pure Loss of Stability for ONR Tumblehome in Following Regular Waves

纯稳性丧失作为5种典型的船舶在波浪中运动失稳的模式之一,是波峰位于船舯时复原力显著减小而导致船舶大幅横摇甚至倾覆的运动失稳现象。论文采用STAR-CCM+商业软件,模拟全附体ONR内倾船在随浪下的纯稳性丧失现象。数值模拟中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,采用欧拉叠加模型进行消波,考虑了实船螺旋桨的旋转因素,对舵进行自动控制来实现航向的稳定。模拟了ONR内倾船在不同航速下发生纯稳性丧失导致大幅横摇甚至倾覆的过程,并与试验结果进行了对比,最大横摇幅值的计算值与试验值趋势一致。分析了在不同航速下舭龙骨、桨、舵等附体力和力矩的变化。论文建立的CFD数值模拟方法,为更加细致地分析波浪中纯稳性丧失的运动现象提供了技术支撑,为后续势流方法中的螺旋桨、舵等附体力学模型的改进提供了参考。

Pure loss of stability is one of the five typical stability failure models and is a nonlinear phenomenon involving a large amplitude of roll motion and capsizing. In this paper, numerical investigations are carried out to simulate pure loss of stability of a fully appended ONRT in following waves using commercial CFD solver STAR-CCM+. Complex ship motions with rotating propellers and moving rudders are calculated using dynamic overset grids, while waves are generated according velocity boundary, and Euler Overlap method is adopted for wave absorbing. Rudder control is applied to keep course. The process of pure loss of stability for ONRT is simulated at various ship speed, with large amplitude roll motion and capsizing involved. Simulation results are compared with experimental data, and maximum roll angles agrees well with experimental data in the tendency. Forces and moments on individual appendages including propellers, rudders and bilge keels are analyzed. The established CFD method offers a reference for improving potential ship models with appendages of propellers and rudders.