Numerical investigation of water-exit hydrodynamics of an axisymmetric body in waves and currents

The water exit of an axisymmetric body represents a typical unsteady multiphase flow process, in which the hydrodynamic forces become highly complex due to dynamic fluid–structure interactions. In this study, the applicability of the Volume of Fluid (VOF) multiphase model, turbulence model, cavitation model, and overset mesh technique was validated through a series of numerical simulations. Based on this framework, the water-exit behaviour of an axisymmetric body was investigated in various hydrodynamic environments. The effects of initial inclination angle, flow direction, and current velocity in a current environment, as well as wave steepness and wave celerity in a wave environment, were systematically examined in relation to the trajectory evolution and hydrodynamic force characteristics during the exit process. The results indicate that a smaller initial inclination angle (i.e. closer to vertical) and lower current velocity reduce the influence on the exit trajectory and force coefficients. In contrast, greater wave steepness and lower wave celerity significantly intensify the impact on both the water-exit trajectory and the associated hydrodynamic loads.