Experimental wind tunnel study on the effect of cyclic yaw rate on wind turbine performance

Cyclic yaw control has emerged as a promising strategy for active wake steering, aiming to mitigate aerodynamic wake interactions and enhance wind farm power generation. This study presents a comprehensive wind tunnel investigation of cyclic yaw control using both single and dual-turbine configurations, with particular focus on the effect of yaw rate on turbine performance and inter-turbine wake dynamics. A triangular waveform yaw modulation strategy is employed, with yaw rates classified as slow (0.5°/s) and fast (1°/s), while maintaining a constant yaw amplitude of 45° to isolate rate-dependent effects. Experimental results reveal that high yaw rates lead to significant improvements in both upstream wake recovery and downstream turbine energy capture. Specifically, under 6 m/s inflow conditions, the downstream turbine operating under fast cyclic yaw control achieves a twofold increase in average electrical efficiency per cycle compared to its static yaw counterpart. Moreover, the effective wake steering range, defined as the yaw interval where downstream turbine efficiency exceeds upstream turbine efficiency, is dramatically expanded, reaching up to eight times that of static yaw at 7 m/s wind speed. By adopting a physically realizable yaw waveform and exploring dynamic response behaviors under different flow regimes, this study provides new insights into the interplay between control rate, wake morphology, and electromechanical power output. These findings not only validate the potential of cyclic yaw control as a practical tool for wind farm optimization but also establish a foundation for future development of adaptive yaw rate control strategies tailored to fluctuating wind conditions.