Research on cavitation and motion characteristics of high-speed vehicles exiting water in underwater salvo

By means of the VOF method for solving the N-S equation, the Schnerr-Sauer cavitation model, SST k-ω turbulence model and 6DOF rigid body motion model, the numerical calculation model of two projectiles exiting water in underwater salvo was established through the overlapping grid technology, and the effectiveness of the numerical method was verified. The supercavity evolution characteristics, the trajectory, deflection angle changes and the drag reduction performance in water exit of the salvo for different launch dimensionless time intervals were studied, and the interference mechanism of the supercavitating flow field was analyzed. The results show that when the two projectiles are launched synchronously in the water-exit process, the expansion of the wall surface of the supercavity inside is restrained, and the supercavity collapses asymmetrically in the water-exit stage. The trajectory stability of the two projectiles is poor, and the maximum deflection angle reaches 3.1°. For water-exit process in the asynchronous launch, the front part of supercavity profiles of the first projectile is basically symmetrical, while the wall of the front part of supercavity profiles inside of the second projectile expands and loses symmetry. With the increase of the launch time interval, the curvature of the front part of supercavity profiles inside of the second projectile decreases. The first projectile can maintain good trajectory stability in the water-exit process. The second projectile deflects inward under the action of the pressure difference, and the motion trajectory also shifts inward. The maximum dimensionless horizontal displacement and maximum deflection angle of the second projectile decrease with the increase of the launch time interval. Compared with the asynchronous launch, the dimensionless vertical velocity of the projectile decays slightly faster under the condition of synchronous launch.