Abstract: “Fluid dynamics of the stall delay phenomenon is studied experimentally in this work on a horizontal - axis wind turbine (HAWT) blade. The 3D - printed blade is produced from a downscaled model of a 5kW HAWT. Its rotational motion in the test section of wind tunnel is precisely controlled by a programmable motor. Both mean static pressures and dynamic pressur es are measured on the suction surface at the spanwise location of 0.25R of the blade at two different global tip speed ratios (TSR) of 3 and 5. The TSR of 3 corresponds to a large angel of attack (AOA) at 30 degrees where the flow is fully separated. The other TSR of 5 corresponds to a smaller AOA of 15 degrees. Planar time - resolved particle image velocimetry measurements at 0.25R for the above two TSRs were performed to study the dynamics of the separated flows when the stall is delayed on the rotating bl ade. The Reynolds numbers at these two TSRs, based on the half chord length of the blade and its relative velocity, are 8683”

Keywords: Stall delay, horizontal-axis wind turbine, static pressure, dynamic pressure, time-resloved particle image velocimetery