Wind turbine power improvement utilizing passive flow control with microtab

In this study, the effect of deploying microtabs on performance improvement of a horizontal axis wind turbine blade is numerically investigated in three-dimensions. The NREL Phase VI, a stall-regulated upwind wind turbine, is used as the baseline case. Different cases are considered to investigate the effects of spanwise location as well as the height variation of tabs along the blade span, on the flow over the rotor blade. In all cases, the tab is located at 95% chord of the airfoil section on the lower surface of the blade. Results reveal that locating microtabs at the outboard part of the blade has a greater impact on the rotor performance than the inboard part. However, both cases improve the output power in comparison with the baseline blade. Furthermore, due to the variations in Reynolds number and local angle of attack along the blade span, the influence of microtab height profile on output power is explored in details. In the best case, 17% of the wasted wind energy in the baseline blade is saved for the sub-rated wind speeds. (C) 2018 Elsevier Ltd. All rights reserved.