Investigation on three-dimensional surrogate model-based simulation of wind turbine wakes

To investigate the characteristics of wind turbine wake flow fields, a novel three-dimensional surrogate model for wind turbines is proposed by representing the rotor as a porous spherical medium. A combined approach of computational fluid dynamics and drone-based field measurements is employed to analyze the wake characteristics in both horizontal and vertical directions for an onshore wind farm in Henan Province, China. Free-stream and wake wind data were acquired using a drone-mounted anemometer system, and a numerical simulation model was developed with modified turbulence parameters. The field-measured inflow conditions were applied as the inlet boundary for simulations. Results indicate that adjusting the porous medium’s drag coefficient effectively captures the rotor's resistance effect. Horizontally, wake velocity and turbulence intensity exhibit symmetric distributions, with a bimodal turbulence profile observed in the near-wake region. Vertically, the wake shows asymmetry: the wind speed at hub height decreases to 46% of the inflow at 2D downstream (D being the rotor diameter) and recovers to 75% at 6D. Turbulence intensity decreases overall, and the tip-induced turbulence enhancement diminishes downstream. Validation against field data shows root mean square errors of simulated velocity within 10%, and turbulence intensity errors mostly within 15%. The proposed model provides an efficient and accurate method for 3D wake simulation, offering potential applications in wind farm layout optimization.