Simulating turbine wakes in floating offshore wind farms

An important consideration when designing and operating a wind farm is how the wakes from the leading turbines affect the performance of the rest of the farm. Upstream turbines generate a wake containing strong spiral vortices, which can lead to reduced efficiency and even structural damage in downstream turbines. Understanding exactly how this wake behaves is crucial, but it can be challenging because every wind farm is unique.

An increasing number of new wind farms are offshore and rely on floating turbines. These structures are moored to the seafloor, in contrast to fixed-bottom turbines, and can move in response to wave, wind, and current loads. This extra motion can make calculating the turbine wake especially difficult.

Kleine et al. developed a numerical model of the wakes of floating turbines in non-turbulent conditions. They determined that the spiral vortices in the wake are the most relevant factors affecting wake conditions and used that information to simplify their model for faster calculations.

“The size of the flow structures created by the turbine motion and the evolution of these modes can be predicted by formulas provided in our article,” said author Vitor Kleine. “Engineers planning floating offshore wind farms will not need to re-run costly simulations to understand the effect of wind and wave conditions on the wake of a turbine.”

The authors plan to extend their work by simulating floating turbines in turbulent environments as well, to investigate the applicability of their model in these conditions. They hope their paper will lead to practical design suggestions for improving efficiency and minimizing damage to turbine structures.

Source: “The stability of wakes of floating wind turbines,” by Vitor Gabriel Kleine, Lucas Franceschini, Bruno Souza Carmo, Ardeshir Hanifi, and Dan Henningson, Physics of Fluids (2022). The article can be accessed at https://doi.org/10.1063/5.0092267 .