Bottom slamming for a Very Large Floating Structure: Coupled global and slamming analyses

An iterative Domain-Decomposition (DD) strategy is developed to examine the coupling between the global motions of a Very Large Floating Structure (VLFS) and bottom-slamming events. It combines (a) the linear-global analysis and (b) the fully-nonlinear description documented in Greco et al. [2008. Bottom slamming for a Very Large Floating Structure: Uncoupled global and slamming analyses. Journal of Fluids and Structures, this issue, doi: 10.1016/j.jfluidstructs.2008.09.002]. Within the DD, (b) is used in an inner domain in the wave-side region of the VLFS, where bottom-slamming can occur. The initial and boundary conditions and the body motions are provided by the global analysis (a). The VLFS motions are then corrected using the global loads induced by slamming. The latter are obtained through a local analytical solution. Assessment of air-entrapment occurring during slamming is discussed, and a pressure criterion is proposed for slamming without air entrainment to switch from the analytical to the numerical evolution of pressure after the impact phase. Comparison with 2-D experiments shows a promising agreement.