Research on the Influence of Launch Velocity on Flow Field and Motion Characteristics of Underwater Vehicles in Wave Environment

During the water-exit process of an underwater-launched vehicle traversing the free surface, the collapse of cavitation envelopes adhering to the vehicle's shoulder generates significant unsteady hydrodynamic loads. This phenomenon is markedly intensified in a wave environment, where dynamic free-surface deformations and multiscale interactions within the cavitating flow field amplify flow complexity. This study employs the fifth-order Stokes wave model, integrated with the Volume of Fluid (VOF) multiphase flow framework and the Schnerr-Sauer cavitation model, to investigate the cavitation evolution characteristics and kinematic response of the vehicle during water exit under varying launch velocities and wave phase conditions. The findings reveal that a reduced cavitation number promotes the development of more pronounced cavitation bubble morphologies at the vehicle's shoulder. In a wave environment, the influence of wave phase on cavitation dynamics during water exit is accentuated, exacerbating the asymmetry of cavitation bubbles between the windward and leeward sides and altering the loci of bubble collapse and detachment. As launch velocity increases, the perturbative effects of the wave environment progressively diminish, leading to a consistent reduction in the vehicle's trajectory deviation and yaw angle. Notably, the mitigation of the yaw angle is more pronounced for vehicles exiting at the wave trough phase with increasing launch velocity.