As the floating offshore wind industry moves toward commercial viability, understanding the interactions between wind turbine wakes and floating structures is becoming increasingly critical. A recent study led by L. Carmo from the National Renewable Energy Laboratory, published in Wind Energy Science, delves into this emerging area of research, specifically focusing on how wakes affect the performance of floating offshore wind turbines (FOWTs).
Traditionally, the behavior of wakes—areas of reduced wind speed behind a turbine—has been well-studied in land-based and bottom-fixed offshore wind turbines. However, the dynamics change significantly when considering floating turbines, which are subject to different environmental forces, such as wave motion. This study aims to bridge that knowledge gap by utilizing FAST.Farm, a simulation tool that has been validated for various conditions but had not yet been specifically tested for floating applications.
In the first phase of the research, Carmo and his team validated FAST.Farm by comparing its simulations of a single FOWT with high-fidelity data from large-eddy simulations found in existing literature. They discovered that the original wake model in FAST.Farm tended to overestimate vertical wake deflection caused by the unique movements of floating turbines. However, the newly developed curled wake model demonstrated improved accuracy in capturing these dynamics.
The second phase involved analyzing a small array of three FOWTs, spaced seven rotor diameters apart, under various environmental conditions. The study adopted the National Renewable Energy Laboratory’s 5 MW reference wind turbine mounted on the OC4-DeepCwind semisubmersible platform. By comparing the results from floating turbines with those from fixed-bottom configurations, the researchers identified key differences. These included how wave-induced motions affect power production and the structural loads experienced by the turbines.
Carmo noted, “The main differences introduced by the floating substructure include the motions induced by the waves, changes in natural frequencies of the tower, and a larger vertical deflection of the wake deficit due to the mean pitch of the platform.” Understanding these factors is crucial for optimizing the design and placement of floating wind farms, which could lead to more efficient energy production.
The implications of this research are significant for the commercial sector. As floating wind technology matures, the insights gained from this study can help developers and engineers design more effective floating wind farms, ultimately leading to increased energy output and reduced costs. This is particularly relevant as countries look to expand their renewable energy portfolios and meet climate goals.
By addressing the complexities of wake interactions in floating wind systems, this research paves the way for more robust and economically viable offshore wind projects. As the industry continues to evolve, studies like this are essential for unlocking the full potential of floating wind technology and driving its adoption on a larger scale.
