Research On Trajectory Characteristics Of Projectile Entering Water Based On Wave Conditions

With the development of science and technology and the increasing competition for marine resources,the seizure of sea control has become an important right in international competition.In order to deal with underwater and underwater threats,the application of air-underwater cross-medium supercavitating projectiles was born.In this paper,a supercavitating projectile is taken as the research object,and the ballistic characteristics of the projectile entering water under wave conditions are studied.The main research contents include:1.Cavitation flow field theory and cross-medium entering water ballistic model research.Based on the theory of cavitation flow field,the principle of independent cross-section expansion and the principle of slender body,the expansion and collapse process of cavitation bubbles are analyzed.At the same time,a prediction model of the cavitation profile of the rotating body entering the water is established.The maximum diameter and half length of the cavitation outline are predicted;the force at the moment when the projectile enters the water and the ballistic model of the supercavitation projectile entering the water are analyzed.2.Numerical simulation study of projectile entering water under wave conditions.By analyzing wave models,control equations,turbulence models,cavitation models,dynamic grids and six degrees of freedom(6DOF)and other technologies,a numerical solution model of the trans-medium supercavitation projectile entering water under wave conditions was established and verified The feasibility of the model is independent of the grid.3.Research on the ballistic characteristics of projectiles entering water under different wave conditions.Based on the established Fluent general simulation model of a cross-medium projectile,The simulation analyzed the ballistic stability and drag reduction characteristics of the projectile entering the water under the conditions of different cone head angles,different flat head area projectiles,different length-diameter ratios,different centroid positions,and different cavitation groove shapes.The simulation results show that the shape of the bullet,the aspect ratio and the position of the center of mass have a greater impact on the projectile’s water stability and drag reduction characteristics,but the shape of the groove has little effect on the two characteristics of the projectile during its entry into the water.The larger the cone angle is,the drag coefficient increases and the ballistic stability decreases;the aspect ratio increases and the projectile’s center of mass is moved forward,which is beneficial to the stability of the projectile into the water.The increase of the cavitation groove will reduce the drag coefficient to a certain extent and improve the ballistic stability.The trajectory characteristics of different projectile structure parameters obtained by the research result...