Sun, ShimingShimingSunYan, KaiKaiYanWang, XiaohuiXiaohuiWangLiu, GuangtaoGuangtaoLiuChu, XuesenXuesenChu2021-03-092021-03-092019-0911th International Workshop on Ship and Marine Hydrodynamics (IWSH2019), Paper 45http://hdl.handle.net/11420/9018The accurate prediction of high speed water entry is very crucial for the research on improving the penetration abilities of underwater vehicles. In this paper, the water entry problem of an axisymmetric blunt vehicle with velocities ranging from 200m/s to 600m/s are numerically studied based on the CFD method. Firstly, the accuracy of the numerical method was verified by experiments. Secondly, the influence of water compressibility on the water entry is studied and it is found that the compressibility will affect impact loads of water entry but has little influence on cavity shapes. Thirdly, the numerical results of cavity shapes during early stages of water entry are compared with the theoretical results based on the principle of independence of the cavity sections expansion. It is found that the numerical results of cavity shape are generally agreed with theoretical results except for the parts near the water surface. Lastly, the main similarity parameters for high speed water entry are also analysed and it is concluded that Mach number is the most important similarity parameter during early stages of water entry at this range of velocities. The results of this paper could provide some guide for the numerical simulations and scaled tests of high-speed water entry.enhttp://rightsstatements.org/vocab/InC/1.0/CavityComputational Fluid Dynamics (CFD)Similarity ruleWater compressibilityWater entryTechnikIngenieurwissenschaftenConference Paper10.15480/882.334510.15480/882.3345Fluiddynamik und Schiffstheorie M-8Other