Analysis Of Loads And Response Of The Structure In Fully Nonlinear Wave

With the increase of survival water depth of ocean engineering structures, more and more researchers have been paying attention to rough environment, which may cause severe damages to offshore structures and seriously affects the normal operation. Especially the strong nonlinear impact phenomenon such as the serious wave run-up around the structure, the large amplitude motion response and green water of the structure, etc, all of these will be induced by the extreme waves. At present, the calculations of wave forces on marine structures are confined to the linear and low-order non-linear wave theories, sometimes these are not satisfied with the requirements. Nowadays, development and application of fully nonlinear wave tank has become one of the hot topics in naval and ocean engineering. In this article, viscous flow theory, fluid-solid coupling theory and free surface tracking technique—VOF(Volume of Fluid) method are based on and continuity equation of incompressible fluid and N-S equation as well as structural dynamics equation are taken as governing equations and fully nonlinear free surface conditions and structural boundary conditions are set to establish viscous numerical wave tank. The following researches are carried out for interaction between fully nonlinear wave and floating structures:(1) In accordance with three classifications the numerical wave tank, interaction between nonlinear and structures and interaction between nonlinear and the elastic structures, made a more comprehensive overview of literatures in domestic and abroad.(2) Based on viscous flow theory, fluid-solid coupling theory and free surface tracking technique--VOF(Volume of Fluid) method, continuity equation of incompressible fluid and N-S equation as well as structural dynamics equations are taken as governing equations and fully nonlinear free surface conditions and structural boundary conditions are adopted to establish mathematical model for interactions between wave and structure and the numerical method is given.(3) Two-dimension and three-dimension viscous numerical wave tanks with effective wave-making and wave-absorbing function are respectively built through UDF programs, which is based on the module FLUENT of CFD included in software package ANSYS14.5.(4) Based on the viscous flow theory, 2-D numerical model for green water on structures is respectively simulated and the results are compared with that of literatures which is to verify the effectiveness of the numerical simulation method.(5) The numerical model of the interaction between fully nonlinear waves and 2D floating structure is established in the numerical wave tank. The influence of wave parameters and freeboard heights on the motion response of structure and green water is analyzed. Afterwards, the numerical model of the interaction between fully nonlinear waves and 3D fixed and free floating structures is established, including the loads on floating body induced by waves, motion response, green water and impact dynamic pressure are carried out in this research. Meanwhile, the mechanism and the complete process of green water are analyzed.(6) Further research is conducted on interaction between the elastic floating structure and waves. The stress and strain of elastic floating structure are analyzed so as to summarize the locations where stress and strain may occur more readily.