The coupled dynamic response computation for a semi-submersible platform of floating offshore wind turbine

Abstract

Many numerical methods based on potential-flow theory have been used to analyze the hydrodynamic effect of floating offshore wind turbine (FOWT). However, they cannot directly and fully consider the complex viscous interference effects for the motion of multi-structure platform geometry. To accurately account for this effect, it necessarily requires an additional numerical modification process based on experimental data or an implementation of Morison equation. This paper deals with an unsteady hydrodynamic simulation using CFD method with dynamic motion based on overset grid and potential based panel approach for the semi-submersible DeepCWind FOWT. Using the CFD approach, the coupled fluid flow and multi-body dynamic analysis is applied using the volume of fluid approach to investigate the hydrodynamic responses of the typical semi-submersible floater. Herein, the restoring force and moment of the catenary mooring lines are also considered in the time-domain. Additionally, a potential flow linear diffraction model extended with and without Morison elements to include viscous damping is performed. It is shown that the present results show good correlations with experimental data without using the adjusting parameters. In addition, numerical tests for major solver parameters of the CFD method are conducted, verified, and investigated in detail.