Design and Hydro-aero-elastic Modeling of a Multi Leg Mooring Concept for Floating Wind Turbine Applications

A multi-cylinder floating structure with conventional catenary mooring lines is presented for supporting a 10 MW Wind Turbine (WT). A design-oriented solution method accounting for the coupled dynamics of the floating structure in the frequency domain is presented and the corresponding RAO's are calculated. The hydrodynamic characteristics are determined using matched axisymmetric eigenfunction expansions. A reduced order model provides the linearized loading contributed by the WT (gravitational, inertial and aerodynamic). In addition, time domain coupled hydro-servo-aero-elastic simulations of the floating structure are performed considering wave excitation described by a white noise spectrum whereby the effective RAO's are computed from the corresponding time signals. Comparison between the two methods is performed at the RAO's level for representative wind speeds and wave heading angles.