FRyFAST : A Coupling Between FRyDoM and OpenFAST for the Simulation of Floating Offshore Wind Turbines With High Complexity Platforms

Abstract

The present paper describes the coupling between two open source software packages, OpenFAST and FRyDoM (named FRyFAST), dedicated to the floating offshore wind turbine (FOWT) dynamics simulation. FRyDoM (Flexible and Rigid body Dynamic modelling for Marine operations) is a multi-body and multi-physics framework, mainly dedicated to complex offshore systems, developed by D-ICE Engineering and Ecole Centrale Nantes. This framework is coupled with OpenFAST in order to simulate FOWT with advanced platform system, corresponding to multi-body system, platform with high interaction with other bodies in close environment or in contact with those bodies. This coupling enables also the used of an advanced Finite Element Model (FEM) based on an iso-geometric representation of the mooring lines. A lot of dedicated models for the platform can also be added through this coupling thanks to the FRyDoM API. In the first part, the coupling between OpenFAST and FRyDoM is presented. Particular attention has been paid to the integration of the added mass term to enable stability of this coupling, and to the synchronization between the two time integration schemes. Verification and validation results of this coupling will be presented. Tension in the mooring lines, dynamic behaviour of the FOWT in different wind and sea conditions have been analysed and show the capacity of this model to perform FOWT design.