Underwater High-speed Movement Of The Projectile External Ballistics Modeling And Simulation

In this paper,the underwater high speed of the small size normal regulations bullet ballistic trajectory model with high muzzle velocity, no momentum and no rolling is builded up, make use of the ballistics theories, torpedo kinetics theories and cavitation mechanism. The simulation program of bullets motion with cavity been programmed, then, the ballistic trajectory characteristics of the underwater high speed moving bullets were calculated and analyzed.The hydrodynamic and ideal liquid force act on the underwater bullets was analyzed. The cavitation mechanism and the super-cavitation phenomenon caused by the bullets moving underwater were studied. The underwater movement equation and it's predigested forms were deduced based on the momentum theorem and the theorem of moment of momentum. On condition of small angle of fire, the approximately analytic resolution of underwater bullets movement is gained, then, make a brief analyses on the factors which influence the range of the underwater bullets. When the hydrodynamic coefficient and ideal liquid force can't be gained exactly, the adoption slice methods are used to solve the hydrodynamic and ideal liquid force act on the underwater bullets. Finally, take some four-cone bullets as example, the hydrodynamic characteristics, the add mass characteristics and the ballistic trajectory characteristics of the underwater high speed moving bullets were analyzed, get these conclusions: 1) Exist a critical velocity v_l, if the velocity of the bullet is less then v_l, the bullet is static unstable; 2) The bullet librated in the bubble, the ballistic trajectory is approximate beeline, the muzzle angle make a huge influence on the trajectory scatter,but the muzzle angular rate do little; 3) The muzzle angle of fire influence valid artillery range of bullets huge;4) The muzzle velocity must be appropriate, the trajectory scatter will be huge if the muzzle velocity is too big; 5) Other characteristics of the bullet underwater movement etc.. The above summing-ups provide certain reference for shape design and trajectory design for thus underwater bullets.