Comparing the Aerodynamic Performance of Floating Offshore Wind Turbines with Optimised and Linearised Blades

Wind turbine blade designs that are aerodynamically optimised for maximum efficiency are known to have a large chord and twist at the inboard sections. Manufacturers have adopted simpler blade designs having a linear chord distribution at the inboard regions. While this has a small effect on the efficiency loss of wind turbines with fixed foundations, the effect of such blade linearization on the aerodynamic performance of floating wind turbines has not been sufficiently dealt with in open literature. This study applies a free-wake vortex model to compare the power and thrust characteristics of floating wind turbines having linearized blades with those having optimised blades. Three- and two-bladed rotors are assumed for different platform surge motions that are representative of different metocean conditions. The study showed that the loss in efficiency through blade linearization is small and similar in magnitude to that encountered in fixed rotors.