Research on flow and drag characteristics of under water successively fired supercavitating projectiles

In order to study supercavities evolution laws and drag characteristics of underwater successively fired projectiles during the natural deceleration, the calculation model of underwater of two or three successively fired projectiles is separately established based on the finite volume method of N-S equation, introduced VOF multiphase flow model and Schnerr-Sauer cavitation model, combined with dynamic grid technology. The evolution law of supercavities induced by underwater two or three successively fired projectiles was obtained. The interaction of pressure fields between multiple projectiles is analyzed. Combined with the evolution law of supercavities, the influence mechanism of supercavities evolution process on projectiles' motion was analyzed. The drag characteristic curves of successively fired projectiles are obtained. The results show that the supercavitating flow fileds of successively fired projectiles interact with each other; the drag force of the latter projectile entering the supercavity of the former projectile is almost zero, and its velocity remains unchanged, while the velocity of the former projectile continues to decay, resulting in the latter projectile catching up with the former projectile and rear-end collision; the shape of supercavity is disturbed at the head of the former projectile and the position of the rear-end collision, the wall of the supercavity with disturbance causes necking and the supercavity gradually split from this position.