Large HAWT (Horizontal-Axis Wind Turbine) wake measurement and analysis

From the theoretical fluid dynamics point of view, the wake region of a large horizontal-axis wind turbine was defined and described, and numerical models of wake behavior were developed. Wind tunnel studies of single turbine wakes and turbine array wakes were used to verify the theory and further refine the numerical models. The effects of scaling, rotor solidity, and topography on wake behavior are questions that remain unanswered. In the wind tunnel studies, turbines were represented by anything from scaled models to tea strainers or wire mesh disks whose solidity was equivalent to that of a typical wind turbine. The scale factor compensation for the difference in Reynolds number between the scale model and an actual turbine is complex, and not typically accounted for. Though it is wise to study the simpler case of wakes in flat topography, current indications are that wind turbine farm development is actually occurring in somewhat more complex terrain.