Wake Development in Floating Wind Turbines: New Insights and Open Dataset from Wind Tunnel Experiments

Abstract. Floating offshore wind turbines represent a promising new technology in offshore renewables, but they are still in their early stages with few prototypes and limited performance data. As part of the NETTUNO research project, this study examines how platform movement affects the aerodynamics of a floating wind turbine rotor and connects its load response to the evolution of its wake. Wind tunnel experiments were performed on a 1:75 scale model wind turbine subjected to platform movements in various directions. Collected data includes measurements of rotor loads and wind speed in the wake of the wind turbine at different downstream distances from the rotor. The study provides a detailed analysis of a selected portion of the data, while the entire dataset is accessible via an open repository. Results indicate that surge and pitch motions induce periodic thrust fluctuations, leading to variations in near wake velocity that peak at a reduced frequency of 0.6. Yaw motion causes oscillations in the yaw moment and lateral wake meandering. Combined surge and sway motions result in skewed apparent wind speed, causing both wake velocity fluctuations and lateral meandering. Increased turbulence intensity near the wake center suggests enhanced wake mixing and potentially a faster recovery beyond a distance of 5 diameters downstream. New experimental data may serve as a foundation for validating numerical simulation tools, while the main findings of the study are thought to provide valuable knowledge for optimizing future large-scale floating wind farms.