Numerical Calculation Of Wave Loads On A 3-D Body Based On NURBS

The interactive force between ship and ocean structures and waves is the most important force to be considered by the designers of the ship and ocean structures. It is vital to ocean structures' life and stability. We can attribute it to the Laplace equations and can use panel method to solve this kind of problems because of its many notable advantages in the occasion of infinite water depth.Since Hess and Smith invented panel method in 1962, panel method has been widely used as a tool for potential flow calculations, such as one order panel method, high order panel method, B-spline and Non-Uniform Rational B-Spline based panel method(NURBS).In this thesis, the author applied NURBS method to construct 3-D geometries and considered free surface boundary conditions which was introduced by Nakos in 1990. Based on Rankine sources, wave loadings on a 3-D body moving beneath free surface are to be calculated. Firstly, The author applied NURBS method to construct 3-D geometries and demarcated grids. Then by satisfying the free surface boundary conditions and body surface boundary condition, the author distributed Rankines sources on the surfaces so that the author could got velocity potiental and solve the corresponding questions.The velocity distribution and pressure distribution was obtained by considering boundary conditions in steady condition. As well as added mass coefficient and damping ing coefficient was obtained in unsteady condition. However, the latter results are less satisifyied than the former results. The results should be improved by reconsidering the boundary conditions.The research is useful for hydrodynamic calculation of the submerged body by using CFD technique.