基于VOF法的平底结构自由落体入水砰击载荷模拟

Numerical simulation on the slamming load in the water-entry process of flatted-bottom body based on the method VOF

应用动网格技术和VOF方法模拟了平底结构的自由落体入水过程和气-液两相流,得到了平底物体自由落体入水过程的运动特性、砰击载荷特性以及入水空泡演化过程。结果表明:整个入水过程中,平底物体在入水瞬间受到来自液面的砰击载荷最大,砰击面的载荷压力分布中间高两端低;砰击载荷随入水初速的增加而增大;平底物体入水空泡破裂后对上表面造成冲击压力。数值计算方法和结果对入水结构安全性和适应性评估具有实际意义。

The volume of fluid( VOF) method coupled with the dynamic mesh method was used to simulate the slamming load on a flatted-bottom body and the liquid-gas multiphase flow during the water-entry process. The unsteady water-entry cavity produced by the flatted-bottom body was analyzed. The flatted-bottom body motion,slamming load,pressure distribution,free surface deformation,and air cushion effect were captured. The evolutionary process of cavity such as its movement and closure was presented. The maximal slamming load occurs at the very beginning and the pressure on the middle part of the bottom surface is higher than that on the edge part. The slamming load increases with the initial velocity of water-entry. Moreover,the water rushes on the surface after the cavity collapse. The numerical calculation method and results are of practical significance for the safety and adaptability assessment of flatted-bottom body during water-entry.