Optimal closed-loop wake steering – Part 2: Diurnal cycle atmospheric boundary layer conditions

Abstract. The magnitude of wake interactions between individual wind turbines depends on the atmospheric stability. We investigate strategies for loss mitigation through use closed-loop steering using large eddy simulations diurnal cycle, in which variations surface heat flux time modify stability, speed and direction, shear, turbulence, other boundary layer (ABL) flow features. control methodology developed Part 1 (Howland et al., 2020c, https://doi.org/10.5194/wes-5-1315-2020) is implemented an example eight turbine farm cycle. optimal yaw misalignment set points depend varies during To improve application transient ABL conditions with evolving mean state, we develop a regression-based direction forecast method. compare to baseline yaw-aligned open-loop lookup table various selections set-point update frequency, dictates balance tracking activity. In our cycle representative geometry, optimization under uncertainty results higher collective energy production than both control. increase simulated design closed- control, compared 4.0 %–4.1 % 3.4 %–3.8 %, respectively, range indicating depending frequency. primary increases occur stable present simulations. Open-loop decreases convective simulated, while simulated.