Prediction of dynamic response of semi-submersible floating offshore wind turbine using Morison's equation and fully coupled nonlinear model

A fully coupled nonlinear simulation tool using an augmented Morison's equation is developed to predict the dynamic response of floating offshore wind turbine (FOWT) system. The hydrodynamic coefficients of a semi-sub model are numerically predicted by using large eddy simulation with volume of fluid method. Firstly, normal and axial distributed hydrodynamic coefficients for each member of the semi-sub model are predicted and the integrated coefficients are validated by water tank tests. Then, the performance of the simulation tool in the prediction of dynamic response of FOWT under different sea states is investigated. Finally, modelling of mooring system is studied to predict the mooring fairlead tension. The dynamic responses of FOWT with improved hydrodynamic models agree well with those measured in water tank tests.