Influence of platform configuration on the hydrodynamic performance of semi-submersibles for offshore wind energy

This work presents a comparison between the hydrodynamic behavior of three and four-column semi-submersibles. The platforms are the NAUTILUS and the OO-star semi-submersibles, with the DTU 10MW wind turbine. Both models are described, and simulations in wind and wave conditions are made using OpenFast. The natural frequencies and the response amplitude operators are calculated. The motions of the platform, the tower bending moment, and the nacelle acceleration are evaluated. These results are assessed to understand whether a particular geometry presents advantages over another. It is concluded that the platform geometry has a slight effect on the platform pitch motion, and economic factors should be considered for model selection.