NUMERICAL STUDY ON GREEN WATER ON DECK AND IMPACT LOADS OF A SHIP MODEL ADVANCING IN HEAD WAVE

Under rough sea conditions, the green water on the ship deck may induce great impact loads on the hull structure, which will cause serious structure damage and pose a threat to the safe ship navigation. Therefore, the study of green water and the impact load is particularly important. In this study, the numerical verification and validation of green water on deck and impact load is carried out. Commercial viscous flow CFD software STAR-CCM+ is used for calculation. The unsteady Reynolds Average Navier-Stokes (URANS) equation is used to numerically solve the process of green water in time domain. The volume of fluid (VOF) method is used to capture the water surface and interface. The model investigated in this study is a modified Wigley ship. Numerical simulation conditions are set according to the experiments conducted in the towing tank at RIAM, Kyushu University. Ship loads and pressure measured at five monitoring points on the deck are compared with experimental data, while the ship motion is fixed in head waves. The numerical uncertainty of time steps and grid sizes is discussed in details. A set of simulation results with appropriate grid and time step are compared with the experimental data. Brief conclusions are given by analyzing the parameter time history, global hydrodynamic force, peak pressure values at gauges and green water process.