Influence of the Rotor characterization on the motion of a floating wind turbine

It is useful to complement model tests of a floating wind turbine with simulations mimicking the scaled-down turbine. Standard engineering tools have some short-comings to model a rotor at the very low Reynolds that Froude scaled wind and rotor's rotation speed impose. The flow around an airfoil at the scale of a wave basin brings new distinct challenges than at full scale. The capacity of standard engineering tools for the design of wind turbines to capture this complexity may be questioned. Therefore, work-around solutions need to be proposed. This paper looks at a common solution that consists of optimizing the load coefficients of the rotor to reproduce the measured rotor loads. 3 variants of optimizations are applied to a semisubmersible floating wind turbine at scale 1/50th, the DeepCwind semisubmersible platform. The effects of the differences between these 3 methods on the motions of the floater in waves and wind are analyzed. In the absence of a controller for the rotor, no significant differences related to the induced aerodynamic damping was noticed, but an offset in the motion related to a thrust deficit was observed.