An Interface of QBlade to the Framework for Floating Offshore Turbine Design Optimization WEIS

Floating Offshore Wind Turbines (FOWTs) are inherently interdisciplinary systems that are excited by a multitude of non-linear external inputs. Figure 1 provides and overview of the main sub-systems that comprise a FOWT and the environment in which they operate. Turbines currently analyzed within the science community possess rotor diameters exceeding 250m and have a rated power of 20 or more megawatt. These large structures experience vastly different aerodynamic conditions depending on the azimuthal position of the blade. At the same time, floating structures are exposed to linear and non-linear wave excitation that potentially cause resonance. The aerodynamic and wave forces cause the floating substructure to move within its rigid degrees of freedom (DOFs), most prominently in surging and pitching motions, causing the turbine to be exposed to negative aerodynamic damping and, at times, interact with its own wake. Due to the rotational speed of the rotor, gyroscopic effects play an increasing role when the turbine undergoes a pitching motion. The continuous motion of the turbine adds to the load requirements thatare posed to a FOWT, compared to their fixed-bottom or onshore counterparts (e.g. on the intersection between floating sub-structure and the tower). To keep the system stable, to maximize annual energy production (AEP), to react to grid events or to secure the system during extreme weather events, a controller manipulates rotational speed and blade pitch during operation.