空气压强对垂直入水空泡影响的数值研究

Numerical simulation of the influence of atmospheric pressure on water-cavity formed by cylinder with vertical water-entry

摘要:

基于RANS方程，结合VOF多相流模型和动网格技术，对带150。锥角头型圆柱体以中等速度垂直 匀速入水空泡进行了数值计算．计算过程中对VOF多相流模型嵌入水和水蒸汽之间的质量输运源项，实现 了水、空气和水蒸汽三项相同时存在的自由液面入水问题数值计算．通过与匀速垂直入水理想空泡模型计算 结果的对比，验证了本文数值计算方法的有效性．对不同空气压强条件下入水空泡形态的数值计算结果分 析，得到了在本文所计算入水工况范围内垂直入水过程中自然空化对入水形态的影响；得到了空泡无量纲闭 合时间、空泡闭合瞬间最大无量纲直径、以及空泡闭合方式与空气压强和入水速度之间的关系等

Abstract:

The dynamics of the water-entry cavity created by vertical water entry of cylinder with 1500 cone nose is simulated based on the Reynolds-Averaged-Navier-Stokes ( RANS) equations, in which the Finite-Vol- ume Method is used in the discretization of the control equations, and the Volume of Fluid Method with the sources of mass transfer due to the natural cavitation is adopted for the multiphase flows of water-entry cavity. The dynamic mesh method is used to control the constant speed of the cylinder. The results show that the non- dimensional time of cavity closure is a function of the atmospheric pressure and the atmospheric density. The cavity closure types depend on the atmospheric pressure and the water-entry velocity greatly. The non-dimen- sional diameter of the cavity created by the cylinder with cone nose at the time of closure is a function of the atmospheric pressure