Combined Experimental-Analytical Predictions of Thrust, Power and Wake Development of a Yaw-Misaligned Horizontal Axis Wind Turbine at High Reynolds numbers

This study examines yaw effects on horizontal axis wind turbine (HAWT) thrust, power, and wake development through a combined experimental-analytical approach. The recently proposed extension to classical actuator disk theory of Heck et al. (J. Fluid Mech. 2023) is examined using complementary experimental data. The experiments are conducted in the High Reynolds number Test Facility at Princeton University, where field-relevant Reynolds numbers (Re_D = 4 × 10⁶) and tip-speed ratios (4 ≤ λ ≤ 7) are achieved by scaling pressure in place of velocity. Yaw angles spanning -45° ≤ γ ≤ 45° are explored, with results showing excellent agreement between measured and model-predicted power outputs. Notably, the model results are fully predictive, with consideration given to thrust coefficient control as function of yaw through the tip-speed ratio, demonstrating a distinct advantage over previous empirical methods (e.g., cos^α(γ) scaling laws). Furthermore, the experimental wake measurements indicate yawing the turbine deflects the wake significantly, while also reducing the wake width and maximum velocity deficit. The results help identify promising directions for future model development, towards the goal of developing a robust, yet simple model for use in real-time wind farm control.