With the shallow sea areas suitable for bottom-fixed offshore wind turbines being increasingly utilised in European waters and with an estimated 80% of Europe's offshore wind resource present in seas with water depths over 50 meters, the advancement of Floating Offshore Wind Energy is the next logical step to increase the share of renewable energy in the energy mix.
The first part of this presentation will give an overview of the type of platforms that are used for Floating Offshore Wind Turbines (FOWT), typical mooring configurations for FOWTs, prototypes of FOWTs that have been developed so far, and past, present and future floating wind projects.
The second part will present the methods for testing and validating FOWT designs. So far, only a few full-scale prototypes have been tested in offshore conditions providing only limited data for the validation of numerical models. Physical scale model testing is therefore an important and cost-effective stage to limit uncertainty in the trajectory from design to prototype development. However, the coupled aero-hydrodynamics of FOWTs (Froude vs Reynolds, gravity dominated hydrodynamics vs viscosity dominated aerodynamics) present certain difficulties at model scale. Froude scaling is applied to the platform, however, when the turbine rotor is geometrically scaled to match that of the platform, its Reynolds number will be lower than at full scale resulting in a lower lift coefficient and a higher drag coefficient at model scale. An overview is given of the methods to overcome these scaling difficulties.