Reconstruction of scaled FOWT blades for achieving aerodynamic similarity with control strategy adjustment

Abstract

It is challenging to simultaneously satisfy Froude and Reynolds similarities in floating offshore wind turbine (FOWT) model tests. This issue causes the thrust and torque of FOWT model to fall short of the desired values. A scaled blade reconstruction method based on the third generation non-dominated sorting genetic algorithm (NSGA-III) and lift force matching is proposed to match the thrust and torque of the FOWT at various speed scales with those of the full model of FOWT. The chord of FOWT blade model is reconstructed based on the lift force matching principle and the chord of prototype blade model. The NSGA-III is used to optimize the control strategy (pitch angle and rotor speed under different wind speeds) to minimize the difference between the thrust and torque of the FOWT model and the desired thrust and torque. The proposed method is applied to reconstruct the blade models for the DTU 10 MW and IEA 15 MW wind turbines at different speed scale ratios, demonstrating its applicability across different turbine types, followed by a performance analysis. The results show that the thrust and torque of the FOWT models after adjusting control strategy closely match the desired values, with most of errors within 5%.