Fluid/Rigid-Body Impact Problem And Study Of Similarity Solution

This paper mainly focuses on the prediction of two dimensional total hydrodynamic loads and similarity solution of fluid/rigid-body.Firstly we make review of all aspects of marine hydrodynamic impact, including description, definition, and analysis of factors affect it, and an introduction of prediction techniques, where their difficulties and advantages and disadvantages are discussed. We give the basic theory and equations used in prediction of hydrodynamic impact in chapter 2.We study the prediction of hydrodynamic impact loads based on Von Karman and Wagner model in chapter 3. The basic principle we adopted is the changing ratio of added mass of the structure at infinite frequency. We compare these two models and investigate their feasibility.We adopt full nonlinear free surface boundary conditions and give various similarity solutions on wedge water entry problem in chapter 4. Numerical simulations are carried out on the vertical water entry of symmetrical wedge and asymmetrical wedge, and then extend to oblique entry of symmetrical and asymmetrical wedge. To get a stable solution, we combine shallow water theory and boundary element method in jet zone. Different styles of water entry problems are studied and their free surface profiles and pressure distributions are presented.In chapter 5, we investigate the similarity solution on the collision of triangle water column and solid structures using the same method as chapter 4, including head on collision of column and vertical/inclined wall, water column hitting on a flat deck, the collision or oblique collision of a water column and a solid wedge, either symmetric or asymmetric. Numerical simulation results are presented and the characteristics of free surface profile, pressure distribution and force are discussed.