Multiphase Flow Simulation of Water-Entry and -Exit of Axisymmetric Bodies

A fully-compressible, multiphase, homogeneous mixture model, based on unsteady Reynolds-averaged Navier-Stokes equations is presented in this study. Dual-time preconditioning method was employed to improve the computational efficiency of the solution. The multiphase flow solver has been applied to computations of: (1) cavitating flows over underwater projectiles; (2) transonic flow past an underwater projectile; (3) water impact of a circular cylinder entering the water; (4) water-entry of a hemisphere with one degree of freedom; and (5) supercavitating flows over an axisymmetric projectile during water-entry and water-exit. The surface pressure coefficients, water impact forces, vertical accelerations, and impact velocities are compared with available experiments and other published results. Good agreements with those results are obtained. Aspects of water-entry and water-exit flow physics of a projectile with and without gaseous exhaust plume including cavity shape, phase topography and drag coefficients are presented.