The realistic three-phase water entry of a free-fall cylinder is investigated in this paper using an efficient lattice Boltzmann method (LBM) with automatic interface capturing capability implemented in an in-house FORTRAN 90 code. The numerical method takes advantage of automatic interface capturing, using a real equation of state (EOS), and considering the surface tension and gas phase compared to the free-surface LBM used for water entry simulations in a few previous LBM works. Simulation results are first compared with other numerical and experimental data with good agreements. Variation of the cylinder trajectory and cavity diameter is presented, and effects of the Froude number, solid density, and surface wettability are investigated. Data analysis shows that the non-dimensional cavity diameter vs. non-dimensional time is independent of the Fr number, or impact velocity, and obeys a power-law trend almost the same as the one reported for variation of the non-dimensional crown diameter for the droplet impact on a liquid film or a deep liquid. The penetration depth during time is almost linearly increased with the impact velocity and solid density. As the surface wettability increases, the penetration depth is reduced, and the deviation of different wettability curves increases with time.

Keywords