Research On Supercavitating Flow And Ballistic Characteristics Of Underwater High-Speed Projectiles In Lateral Flow

The problem of supercavitation of underwater projectiles in oceanic lateral flow environments originates from the use of underwater weapons in real naval battles.In order to enhance the effectiveness of striking underwater targets,many countries are conducting relevant research on the flow behavior,mechanism,and laws of supercavitating projectiles,striving to develop underwater cluster projectile weapon systems that can be continuously fired in series or simultaneously fired in parallel.In this paper,numerical simulation studies on cavity evolution and projectile motion are conducted for the supercavitation of series and parallel double-fired underwater projectiles in oceanic lateral flow environments,which has significant military and academic research value.This paper establishes a numerical calculation method for solving the supercavitation flow field and trajectory of high-speed underwater projectiles based on the VOF multiphase flow model,RNG k-εturbulence model,Schnerr-Sauer cavitation model,and six-degree-of-freedom equations of motion for moving bodies.The method uses overlapping grid technology with adaptive motion boundary changes for projectiles.After verifying its accuracy,this paper analyzes and compares the supercavitation evolution process and trajectory characteristics of single,parallel,and series double-fired projectiles under different lateral flow velocities and angles,revealing the dynamic mechanism and influence regularity of the attitude change of the projectiles.The main conclusions of this paper are as follows:(1)In lateral flow conditions,the cavitation generated by a single underwater projectile is not symmetrical,and wetting phenomenon will occur at the tail of the oncoming side of the projectile.Moreover,the larger the lateral flow velocity,the greater the offset velocity,deviation amount,and deflection angle of the projectile at the same moment,and the poorer the stability of the projectile’s trajectory.As the lateral flow angleβapproaches 90~°,the asymmetry of the cavity becomes stronger,and the deviation speed,deviation amount,and deflection angle of the projectile also become larger.(2)In the absence of lateral flow,the supercavitation generated by a single projectile in an underwater parallel projectile group is not symmetrical,while the supercavitation generated by the entire parallel projectile group is symmetrical.The two projectiles in the group tend to deflect away from each other at the head.In the presence of lateral flow,neither the single projectile nor the entire projectile group generates symmetrical supercavitation.The inside tail of the upstream side projectile is more likely to experience wetting.As the lateral flow velocity increases,the deflection of the upstream side projectile decreases while the deflection of the downstream side projectile increases.Surprisingly,the stability of the projectile on the upstream side is better than that on the downstream side.(3)In the absence of lateral flow,the rear-fired projectile of the underwater series projectile enters the cavity generated by the front-fired projectile and continues to move until it catches up with the front-fired projectile.In the presence of lateral flow,when the lateral flow velocity reaches a certain value,the rear-fired projectile is difficult to enter the cavity generated by the front-fired projectile.Under the same lateral flow velocity,as theβvalue gradually approaches 90~°,the deviation speed of the two projectiles gradually increases.Compared with the front-fired projectile,the deviation angle and trajectory variation of the rear-fired projectile are more complex,and the stability is worse.