Status: this preprint is currently under review for the journal WES.
The Dynamic Coupling Between the Pulse Wake Mixing Strategy and Floating Wind Turbines
Daniel Graham van den Berg1,Delphine de Tavernier2,and Jan-Willem van Wingerden1Daniel Graham van den Berg et al.Daniel Graham van den Berg1,Delphine de Tavernier2,and Jan-Willem van Wingerden1
Received: 12 Dec 2022 – Discussion started: 18 Jan 2023
Abstract. In recent years control techniques such as dynamic induction control (often referred to as "The Pulse'') have shown great potential in increasing wake mixing with the goal of minimizing turbine-to-turbine interaction within a wind farm. Dynamic induction control disturbs the wake by varying the thrust of the turbine over time, which results in a time-varying induction zone. If applied to a floating wind turbine, this time-varying thrust force will, besides changing the wake, change the motion of the platform. This work investigates if the coupling between the Pulse and floater dynamics has an impact on the wake mixing performance of the Pulse. This is done by considering first the magnitude of motions of the floating wind turbine due to the application of a time-varying thrust force and secondly the effect of these motions on the wake mixing. A frequency response experiment shows that the movement of the floating turbine is heavily frequency-dependent, as is the thrust force. Time domain simulations, using a free wake vortex method with uniform inflow, show that the expected gain in average wind speed at a distance of five rotor diameters downstream is more sensitive to the excitation frequency compared to a bottom-fixed turbine with the same Pulse applied. This is due to the fact that platform motion decreases the thrust force variation and thus reduces the onset of wake mixing.
Wind turbines placed in farms interact with their wake lowering the power production of the wind farm. This can be mitigated using so-called wake mixing techniques. This work investigates the coupling between the Pulse wake mixing technique and the motion of floating wind turbines using the Pulse. Frequency response experiments and time-domain simulations show that extra movement is undesired and the 'optimal' excitation frequency is heavily platform-dependent.
Wind turbines placed in farms interact with their wake lowering the power production of the wind...