Simulation Study On High Speed Water Entry Of Rotating Projectile

In recent years,the projectile with stable tail fin has been able to navigate underwater for a long distance.However,a large number of studies show that the projectile is more prone to instability and the trajectory is more complex when it enters the water and flies underwater at high speed.It is of great practical significance to study the effects of projectile structural parameters and water entry conditions on the water entry of small aspect ratio rotating projectile,so as to improve the water entry stability of small aspect ratio high-speed rotating projectile.In this paper,taking the the water entry process of the high speed rotating projectile as the research object,the cavitation characteristics,hydrodynamic characteristics and ballistic characteristics of the high-speed rotating projectile under different structure and motion conditions are studied by numerical simulaition.The effects of the initial motion parameters and structural parameters of the projectile on its water entry characteristics are analyzed,and the main influencing factors of the small aspect ratio rotating projectile in the water entry process are discussed.The main research contents and results are as follows:(1)Based on the Navier-Stokes equation and VOF multiphase flow model,the numerical model of high-speed rotating projectile with small aspect ratio in three-dimensional space is established.The numerical model and calculation method is validated by comparing with the classical empirical formula and experimental results.(2)The numerical simulation of small aspect ratio high-speed rotating projectile entering the water is carried out,and the effects of rotating speed,velocity,center of gravity position,aspect ratio,cavitator size,projectile head cone angle and water entry angle on the cavitation shape,projectile hydrodynamic characteristics and projectile path characteristics of small aspect ratio high-speed rotating projectile entering the water are studied,On this basis,the effects of structure and motion parameters of small aspect ratio rotating projectile on its water entry stability are analyzed.(3)Based on the analysis of the influence of the structure and motion parameters of the rotating projectile on its water entry stability,some suggestions for designing the high-speed rotating projectile with stable water entry are given.