Research On The Trajectory Characteristics And Motion Simulation Of Supercavitating High Speed Projectile In The Variable Medium

To study the kinetic characteristic of supercavitating high-speed projectile in the process of variable medium is a trend to adapt to different operational environments in the future.Supercavitating projectile with high-speed in the process of water-entry and water-exit contain complex phenomena such as phase change,through the gas-water surface,turbulence and so on.It has fluid characteristics such as high nonlinear behavior,high-load situation,unsteady situation and so on.Meanwhile it is accompanied by the changes of flow field,e.g.spatter,tail slapping,water impact,opening and closing the surface of cavity,these direct influnce the projectile’s process of water-entry and water-exit.This thesis applies the combination of theoretical analysis and numerical calculation,based on a certain caliber supercavitating projectile as the research object,to analyze the trajectory characteristics in a variable medium environment and the stability of water-entry and water-exit for it.The specific topics of this thesis are as follows:In order to analyze the trajectory characteristics of the supercavitatiing projectile in the variable medium environment,through establishing the reference coordinate system of high-speed projectile and the force analysis of the projectile in the stage of water-entry and water-exit.the general spatial motion equation and dynamic equations of the supercavitation projectile are constructed,it lays the foundation for the follow-up analysis.The basic theory of hydrodynamics and numerical simulation calculation method for supercavitating projectile in variable medium environment are briefly analyzed,The six-degree-freedom equation based on a certain caliber high-speed projectile is established.The discrete solution method and the calculation boundary condition are analyzed with the dynamic grid technology.Based on the numerical simulation method of Reynolds-averaged Navier-Stokes equations,the trajectory simulation analysis are carried out for a certain caliber high-speed projectile in the process of water-entry and water-exit,under the factors of different rotational speeds,different angles,different initial speeds,and so on.The specific analysis projectile’s kinetic characteristic as motion trails,velocity,angular velocity and resistance in the process of variable medium.the characteristics and phenomena of fluid in the process of variable medium are also described briefly.get the rotational speed,angle and initial velocity are all factors that affect the stability of the projectile’s process of water-entry and water-exit,the rotation of the projectile is not conducive to variable medium motion,the stability of the nonrotating projectile water-entry and water-exit at the right speed is the best.The research results in this thesis provide some reference value about theoretical and engineering for the kinetic characteristic annlysis of high-speed projectile in the variable medium environment.