Numerical Investigation on Cavity Evolution and Motion Characteristics of High Speed Water Entry Ogival Projectiles with Different Headforms

At present, The trans-media weapon is one of research hotspot in the military field. Based on the reynolds time-averaged N-S equation, VOF multiphase flow model and modified Realizable k-ε turbulence model, a three-dimensional numerical simulation method is constructed to study the cavity evolution and motion characteristics of ogival nose projectiles with different head shapes during high-speed vertical water entry, and the influence of head shapes on the cavitation evolution and motion characteristics is analyzed. The results show that the numerical simulation and experimental data have good consistency in the evolution of cavity shape and projectiles velocity. The geometry of the projectile warhead significantly affects the formation mechanism of the cavity and the motion characteristics of the projectiles. The cavity of ogival nose projectiles and double-cone ogival nose projectiles initially appears in the shoulder area of the projectile body, while the cavity of cone-cylinder ogival nose projectiles starts in the head and quickly wraps the entire projectile body. Combined with the analysis of the fluid pressure field, it is shown that a low-pressure area appears on the double-cone ogival nose projectile, which leads to the slowdown of the projectile velocity attenuation. The head of the cone-cylinder ogival nose projectile forms a typical high-pressure area, which leads to the acceleration of the projectile velocity attenuation. In addition, the axial acceleration of the cone-cylinder ogival nose projectile is more than twice that of the other two projectiles.