CFD-Based Numerical Wave Basin for Floating Offshore Wind Turbines

Abstract

Abstract This paper introduces a novel coupled analysis methodology for predicting the global responses of floating offshore wind turbine (FOWT) platforms using high-fidelity Computational Fluid Dynamics (CFD) analysis. The hydrodynamic behavior of the floating platform subjected to waves and current is solved by T.EN's CFD-based numerical wave basin tool (MrNWB), and the aerodynamic, aeroelastic, and servo-dynamic behaviors of a wind turbine are solved by NREL's wind turbine simulation tool (OpenFAST). The present numerical wave basin tool is called Wind Turbine Numerical Wave Basin (WTNWB) and is capable of providing wind-turbine performances and tower structural responses as well as 6-DOF platform motions and mooring tensions in high-fidelity. The coupled analysis demonstrates excellent agreement with the model test in the prediction of platform motions and mooring line tensions. WTNWB can overcome known drawbacks of two types of physical model testing methods: full physical model testing and real-time hybrid model testing. WTNWB is now ready to be used in FOWT projects for global performance analysis and is capable of more complicated test cases to consider blade elasticity, pitch control, and other possible sensitivity tests available in OpenFAST.