Simulation of the wake vortex and trajectory characteristics of successively launched multiple projectiles

This paper analyzes the influence of the Froude number on the flow field interference and trajectory characteristics of successively launched underwater multiple projectiles. The realizable k−ε turbulence model, and overlapping grid techniques have been adopted. At the same time, a numerical method verification and grid independence validation are presented. The flow field structure, wake vortex, pressure distribution and trajectory characteristics are studied. The results show that the gas mass in the flow field consists of three parts: the gas mass connected to the launch tube, the cavity attached to the projectile tail, and the free gas mass. In the wake, a hairpin vortex packet composed of a multistage hairpin vortex is the main vortex structure. As the Froude number increases under a downwind launch sequence with the wind side first, the number of hairpin vortex stages increases. When the second projectile encounters a hairpin vortex packet, there are significant effects on the pressure distribution and trajectory characteristics. Fortunately, less interference occurs between double projectiles during the upwind launch sequence with the lee ward side traveling first. Therefore, to increase the success rate of successively launched underwater projectiles, the upwind launch sequence with the lee side first is adopted whenever possible.