Comparisons of the dynamical characteristics of a semi-submersible floating offshore wind turbine based on two different blade concepts

Scaled model tests are important for the development and validation of floating offshore wind turbines. However, it has been found that Reynolds number dissimilitude between scales deteriorates the aerodynamic performance of floating offshore wind turbines when using model test investigation methodologies. To overcome this challenge, a semi-submersible floating offshore wind turbine model test with two different solutions, namely a geometrically matched blade model and a performance-matched blade model, was conducted in a wind/wave basin. Subsequently, a series of comparisons of the dynamical characteristics of these two models were made to clarify the respective validity of the two models and provide references for future floating offshore wind turbine model optimization. It is found that both model methods are capable of reflecting the essential dynamical characteristics but there are some differences in system eigenfrequencies and response amplitudes. Compared with the geometrically matched blade model, the performance-matched blade model has enhanced aerodynamic performance. Nevertheless, the overweight blades within the performance-matched blade model yields inevitable discrepancies compared with the original design.