Wind loads on floating offshore wind turbines (FOWTs) consist of steady and dynamic components and turbulence is the primary characteristic that differentiates their effects. Industry practice has largely focused on steady winds in the design of floating wind turbines, and emphasis on the effects of turbulence has been inadequate. The extent to which turbulence can affect global responses of FOWTs is not sufficiently understood, and is necessary for the design of safe and robust systems. It is known that turbulence can significantly affect the potential for wind turbines to harness required energy from wind fields. For FOWTs, there is valid concern about the extent to which the functionality and safety of the wind turbine system may be hampered, through interactions between the hydrodynamics-induced platform motions, and turbulence-induced motions of the rotor and tower.
Sequel to a prior study addressing the steady-wind aerodynamic effects on the global responses of a 5MW wind turbine three-column TLP, this study investigates the impact of wind turbulence on the global motions, tendon tensions, nacelle accelerations, generated power and tower base responses for the same floating system. The Kaimal and Von Karman wind spectra models (which are some of the most widely used models in offshore wind analysis) are implemented in this study. Results from the steady-wind and turbulent-wind studies are compared and discussed to delineate the effects of wind turbulence. Lessons learned from this study are applicable to any type of FOWT platform and can be effectively incorporated in design with the advantage of achieving safer, robust and optimal FOWT systems.