Numerical simulations for water entry of hydrophobic objects

Based on the boundary data immersion method (BDIM) and the volume of fluid (VOF) method, the water entry process of hydrophobic objects is numerically simulated. The water crown, the cavity and the flow pattern are analyzed. In the present study, the cavity shape caused by the water entry and trajectories of objects are simulated by the numerical method. Simulation results are compared with experimental data, and the comparisons show that the present numerical approach has the ability to predict the complex process of water entry as well as the effects of the density of an object and entry velocity. Numerical results indicate that the depth of pinch-off increases as reducing the characteristic length of the cavity; the pinch-off time increases for the sphere with a larger density; the depth of cylinder, where occurs the cavity shape inversion behavior, is not affected by the entry velocity of the cylinder.