Aerodynam·ic Pressure and Flow-Visualization Measurement from a Rotating Wind Turbine Blade

Aerodynamic, load, flow-visualization, and inflow measurements have been made on a 10-m, three-bladed, downwind, horizontal-axis wind turbine ( HAWT). A video camera mounted on the rotor was used to record night­ time and daytime video images of tufts attached to the low-pressure side of a constant-chord, zero-twist blade. Load measurements were made using strain gages mounted at every 10% of the blade 1 s span. Pressure measurements were made at 80% of the blade's span. Pressure taps were located at 32 chordwise positions, revealing pressure d i st ribut ions comparable with wind tunnel data. Inflow was measured using a vertical­ plane array of eight propvane and five triaxial (U-V-W) prop-type anemometers located 10 m upwind in the predominant wind direction. One objective of this comprehensive research pro­ gram was to study the effects of blade rotation on aerodynamic behavior below, near, and beyond stall. To this end, flow patterns are presented here that reveal the dynamic and steady behavior of flow conditions on the blade. Pressure distributions are compared to flow patterns and two-dimensional wind tunnel data. Separa­ tion boundary locations are shown that change as a function of spanwise location, pitch angle, and wind speed.