Although nonlinear wave hydrodynamics has received a very large number of studies over the last three decades, computation of very steep and/or overturning waves, their loads on offshore structures as well as responses of the floating structures is still of a very challenge and time-consuming task, particularly associated with fully nonlinear interaction between waves and three-dimensional (3D) freely-floating structures, for which the results are very limited at present. Recently, a method called QALE-FEM (Quasi Arbitrary Lagrangian-Eulerian Finite Element Method) has been developed by the authors of the paper, which is based on full nonlinear potential theory (FNPT). The method can be and has been applied to various nonlinear wave problems including overturning waves and also to fully nonlinear and fully coupled interaction between waves and structures. Numerical investigations have shown that the QALE-FEM can be many times faster than other methods based on the same theory and can produce results that agree reasonably well with experimental data available in literature. This paper will discuss the main features of the method and present some typical examples to demonstrate its flexibility and powerfulness.
So far, a large number of studies have been carried out on waves and wave-body interactions. However, computation of very steep and/or overturning waves, their loads on offshore structures as well as responses of the floating structures is still of a very challenge and timeconsuming task. Because of the strong nonlinearity involved sometimes, solutions based on linear or other simplified theories may be insufficient and so fully nonlinear theory is necessary. Two types of fully nonlinear models, i.e. NS model (governed by the Navier-Stokes and the continuity equations together with proper boundary conditions) and FNPT models (fully nonlinear potential model), may be used.
