二维楔形物体的自由撞水分析

Free water impacting analysis of a two-dimensional wedge

为分析物体在撞水过程中由于加速度急剧变化而对其运行有效性和安全性的影响,基于速度势理论,采用任意的Lagrangian-Eulerian(ALE)边界元法分析二维楔形体的自由撞水,并预设自由液面网格点的运动轨迹平行于结构面.对一斜升角楔形体自由撞水实验结果与数值计算结果的比较验证了该计算方法的可靠性,同时,获得了液固耦合面上的无量纲水动压力分布随时间变化规律.另外,参数比较研究发现,斜升角或质量减小时,加速度变化速度加快,加速度峰值降低,达到峰值所需的时间缩短,相同参数增量下的峰值变化幅度增大;而初速度增大时,加速度-时间历程具有相同的变化趋势.

To analyze the effects of the body on its efficiency and safety of running with rapid change of acceleration during water impact,a simulation of 2D wedge with deadrise angle freefall into water was developed based on the potential flow theory,and impacting performance was analyzed with arbitrary Lagrangian-Eulerian（ALE） boundary element method for which the trajectories of free surface＇s nodes parallel to structural surfaces were presupposed.Comparing results between numerical calculation and experiments verify the reliability of the proposed method.The law of nondimensional water dynamic distribution change with time was obtained.Moreover,comparative studies show that the variation rate of wedge＇s acceleration becomes greater with the decrease of deadrise angle or mass,peak acceleration becomes lower,and reached time of peak acceleration is shorter and the range of peak variation with the same parameter increment becomes larger.When initial impacting velocity increases,the course of acceleration along with the time has the same variation tendencies.