Unsteady flows can power the next generation of wind-energy technologies

Since flows in the atmospheric boundary layer are dominated by turbulence, wind-energy systems are constantly exposed to unsteady flow conditions. Unsteady flows can induce large variations in wind-turbine and wind-farm power generation and amplify fatigue loads on turbine blades and drivetrain components, thereby playing a central role in setting the levelized cost of energy for wind power. These effects are particularly salient in offshore wind farms, where large, flexible turbine blades and the motions of floating platforms unlock additional degrees of freedom for time-varying dynamics. Therefore, unsteady flows in wind-energy contexts represent a crucial area of research for the global clean-energy transition.

In this talk, I will review recent advances in the physics of streamwise unsteady flows for wind-energy applications, including time-varying inflow and wake dynamics of fixed-bottom turbines and streamwise surge motions in floating-offshore wind turbines. Theoretical, experimental, and numerical results suggest that performance enhancements of several percentage points may be achieved by wind-energy systems that account for and leverage unsteady flows. These dynamics can be captured in simple first-principles models and applied in turbine- and farm-level control strategies, such as active wake mixing. This body of work represents just one of a multitude of ways in which fundamental fluid mechanics can inspire solutions to the world’s energy and climate challenges.