Green water loading on a floating structure with degree of freedom effects

The aim of the present work is to investigate whether the degree of freedom (DOF) of a floating body has a notable effect on the maximum impact pressure due to green water on deck. The analysis is carried out for a box-shaped floating structure with a deckhouse, using experimental and numerical means to model the green water load. Green water on deck and impact on the deckhouse is generated by the impingement of a focusing wave group on a floating structure. Computations are performed using a two-dimensional constrained interpolation profile-based model solving the Navier-Stokes (N-S) equations with free surface boundary condition to deal with nonlinear water-structure interactions. The free surface is captured by a volume of fluid (VOF)-type tangent of hyperbola for interface capturing/slope weighting (THINC/SW), which is more accurate than the original THINC scheme. The verifications of the simulation through a series of model-to-model comparisons are performed in a two-dimensional glass-wall wave tank. Experimental water surface elevations, body motions and impact pressure are compared satisfactorily with the computed results for different DOFs cases. As a result, the peak impact pressure due to green water decreases rapidly with the increasing DOF.