滑落式救生艇入水阶段运动响应数值预报研究

Numerical prediction of the motion response of a lifeboat sliding into the water

针对滑落式救生艇入水阶段涉及到固液耦合、自由液面变形等复杂水动力学问题,且入水过程极短现象难以捕获,本文基于雷诺时均方程,采用重叠网格技术处理大尺度运动问题,耦合求解救生艇前进、垂荡和纵摇3个自由度运动方程,构建了滑落式救生艇入水阶段运动响应数值预报方法,探讨了初始垂向速度、水平速度和纵倾角等参数对救生艇运动响应的影响,定量分析了艇体入水阶段垂向和水平加速度及速度变化规律、艇体入水深度与前冲距离、艇体纵倾角变化规律,数值结果可为实艇抛落、模拟训练系统提供可靠的理论和技术支撑。从安全性和快速逃离来看,救生艇入水的垂向速度不超过29 m/s,纵倾角不超过45°。

In view of the complicated hydrodynamic problems such as solid-liquid coupling and free liquid sur⁃face deformation involved in the water entry of freefall lifeboat,and the water entry process is very short is diffi⁃cult to capture.The overlapping grid technology based on the Reynolds time-averaged RANS equation is employed in this paper to deal with large-scale motion problems,along with the solution of the three-degree-of-free⁃dom motion equations of the lifeboat forward,heaving,and pitching.We established a set of numerical prediction methods for the motion response of the sliding-down lifeboat in the entry stage to discuss the influence of the horizontal speed,initial vertical speed,and trim angle on the motion performance of the lifeboat.At the same time,we quantitatively analyzed the vertical and horizontal acceleration and the speed change law of the hull in the entry stage,the depth of the hull into the water,the forward distance,and the change law of the hull trim angle,the numerical results can provide reliable theoretical and technical support for the launching and simulation training system of real boat.From the point of view of safety and quick escape,the vertical speed of the lifeboat entering the water does not exceed 29 m/s,and the longitudinal Angle does not exceed 45°.