A time-domain second-order FEM model for the wave diffraction-radiation problem. Validation with a semisubmersible platform

A finite element method for the solution of the up-to-second-order wave diffraction-radiation problem in the time-domain is proposed. The solver has been verified against available analytical solutions, and validated using experimental data available for the HiPRWind semisubmersible platform (designed for floating wind turbines). To validate, the wave diffraction-radiation solver is coupled to body dynamics and mooring solvers in the time-domain. The HiPRWind movements and mooring forces have been compared for a large number of test cases, including decay tests, monochromatic waves, and bichromatic waves obtaining good correlation for both body movements and mooring forces. •FEM Potential flow for the second-order wave diffraction-radiation problem.•Unstructured meshes were used.•Extensive validation including the effect of non-linear dynamic mooring.