Flow separation frequently occurs in the inboard region of wind turbine blades, leading to degraded aerodynamic performance. A flow deflector (FD) is proposed as a passive flow control approach for wind turbines. The FD consists of a column of small flat plates mounted near the blade leading edge. Numerical simulations based on the transition SST model are conducted to investigate the flow control mechanism and its effects on blade flow structure and aerodynamic performance. The results show that the FD effectively deflects the local inflow toward the blade surface, guiding high-speed flow to energize the boundary layer. Therefore, flow separation is substantially suppressed, and both shaft torque and power coefficient are improved. The FD enhances sectional power output over 38.8% < r/R < 80.0%, extending beyond its installation region in the spanwise direction due to three-dimensional rotational effects. In addition, FD geometric parameters strongly influence blade aerodynamic performance. With an optimal FD configuration, the shaft torque and power coefficient increase by 18.24%, 20.77%, 7.90%, and 20.82% at wind speeds of 10, 11, 13, and 15 m/s, respectively.
ZhangYRamdossVSaleemZ, et al.Effects of root gurney flaps on the aerodynamic performance of a horizontal axis wind turbine. Energy2019; 187: 115955. https://doi.org/10.1016/j.energy.2019.115955
ZhuCQiuYFengY, et al.Combined effect of passive vortex generators and leading-edge roughness on dynamic stall of the wind turbine airfoil. Energ Convers Mange2022; 251: 115015. https://doi.org/10.1016/j.enconman.2021.115015
8.
ÖzdenMGençMSKocaK. Passive flow control application using single and double vortex generator on S809 wind turbine airfoil. Energies2023; 16(14): 1–17. https://doi.org/10.3390/en16145339
9.
BakhtiariNBJa'FariMJaworskiAJ, et al.Passive control of boundary layer flow separation on a wind turbine airfoil using vortex generators and slot. Ocean Eng2023; 283: 115170. https://doi.org/10.1016/j.oceaneng.2023.115170
ZhuCChenJQiuY, et al.Numerical investigation into rotational augmentation with passive vortex generators on the NREL phase VI blade. Energy2021; 223: 120089. https://doi.org/10.1016/j.energy.2021.120089
12.
JiangRZhaoZLiuY, et al.Numerical study on the influence of vortex generators on wind turbine aerodynamic performance considering rotational effect. Renew Energy2022; 186: 730–741. https://doi.org/10.1016/j.renene.2022.01.026
13.
ZhongJLiJLiuH. Dynamic mode decomposition analysis of flow separation control on wind turbine airfoil using leading-edge rod. Energy2023; 268: 126656. https://doi.org/10.1016/j.energy.2023.126656
14.
ÖzdenMGençMSKocaK. Investigation of the effect of hidden vortex generator-flap integrated mechanism revealed in low velocities on wind turbine blade flow. Energ Convers Mange2023; 287: 117107. https://doi.org/10.1016/j.enconman.2023.117107
15.
AzlanFTanMKTanBT, et al.Passive flow-field control using dimples for performance enhancement of horizontal axis wind turbine. Energy2023; 271: 127090. https://doi.org/10.1016/j.energy.2023.127090
TariqUAdeelJAliA. Computational evaluation of an optimum leading-edge slat deflection angle for dynamic stall control in a novel urban-scale vertical axis wind turbine for low wind speed operation. Sustain Energy Techn2020; 40: 100748. https://doi.org/10.1016/j.seta.2020.100748
18.
MoshfeghiMHurN. Power generation enhancement in a horizontal axis wind turbine blade using split blades. J Wind Eng Ind Aerod2020; 206: 104352. https://doi.org/10.1016/j.jweia.2020.104352
19.
MoshfeghiMShamsSHurN. Design and aerodynamic performance analysis of a finite span double-split S809 configuration for passive flow control in wind turbines and comparison with single-split geometries. J Wind Eng Ind Aerod2021; 214: 104654. https://doi.org/10.1016/j.jweia.2021.104654
20.
BhavsarHRoySNiyasH. Aerodynamic performance enhancement of the DU99W405 airfoil for horizontal axis wind turbines using slotted airfoil configuration. Energy2023; 263: 125666. https://doi.org/10.1016/j.energy.2022.125666
21.
GaunaaMZahleFSørensen NN, et al. Quantification of the effects of using slats on the inner part of a 10MW rotor. Proceedings of EWEA 2012 - European Wind Energy Conference & Exhibition. European Wind Energy Association (EWEA), 2012, vol 2, pp. 919–930. https://doi.org/10.4276/030802212X13383757345265
22.
LiYWangHWuZ. Aerodynamic characteristic of wind turbine with the leading edge slat and Microtab. Sustain Energy Techn2022; 52: 101957. https://doi.org/10.1016/j.seta.2022.101957
23.
ZakiAAbdelrahmanMAAyadSS, et al.Effects of leading edge slat on the aerodynamic performance of low Reynolds number horizontal axis wind turbine. Energy2022; 239: 122338. https://doi.org/10.1016/j.energy.2021.122338
24.
LinYTChiuPH. Influence of leading-edge protuberances of fx63 airfoil for horizontal-axis wind turbine on power performance. Sustain Energy Techn2020; 38: 100675. https://doi.org/10.1016/j.seta.2020.100675
25.
HuangSQiuHWangY. Aerodynamic performance of horizontal axis wind turbine with application of dolphin head-shape and lever movement of skeleton bionic airfoils. Energ Convers Mange2022; 267: 115803. https://doi.org/10.1016/j.enconman.2022.115803
26.
ChenMZhaoZLiuH, et al.Research on the parametric modelling approach of vortex generator on wind turbine airfoil. Front Energy Res2021; 9: 726721. https://doi.org/10.3389/fenrg.2021.726721
27.
WongKHChongWTSukimanNL, et al.Experimental and simulation investigation into the effects of a flat plate deflector on vertical axis wind turbine. Energ Convers Mange2018; 160: 109–125. https://doi.org/10.1016/j.enconman.2018.01.029
28.
QasemiKAzadani LN. Optimization of the power output of a vertical axis wind turbine augmented with a flat plate deflector. Energy2020; 202: 117745. https://doi.org/10.1016/j.energy.2020.117745
29.
ChenWHWangJSChangMH, et al.Efficiency improvement of a vertical-axis wind turbine using a deflector optimized by Taguchi approach with modified additive method. Energ Convers Mange2021; 245: 114609. https://doi.org/10.1016/j.enconman.2021.114609
30.
LayeghmandKGhiasi TabariNZarkeshM. Improving efficiency of Savonius wind turbine by means of an airfoil-shaped deflector. J Braz Soc Mech Sci Eng2020; 42: 1–12. https://doi.org/10.1007/s40430-020-02598-7
31.
MaldarNRYeeNCOguzE, et al.Performance investigation of a drag-based hydrokinetic turbine considering the effect of deflector, flow velocity, and blade shape. Ocean Eng2022; 266: 112765. https://doi.org/10.1016/j.oceaneng.2022.112765
32.
AbbasiSDaraeeMA. Improving vertical-axis wind turbine performance through innovative combination of deflector and plasma actuator. Phys Fluids2024; 36(4): 045134. https://doi.org/10.1063/5.0204070
33.
JiangYZhaoPStoesserT, et al.Experimental and numerical investigation of twin vertical axis wind turbines with a deflector. Energ Convers Mange2020; 209: 112588. https://doi.org/10.1016/j.enconman.2020.112588
ZhangRKWuJZ. Aerodynamic characteristics of wind turbine blades with a sinusoidal leading edge. Wind Energy2012; 15: 407–424. https://doi.org/10.1002/we.479
37.
HuangXMoghadamSMAMeysonnatPS, et al.Numerical analysis of the effect of flaps on the tip vortex of a wind turbine blade. Int J Heat Fluid Flow2019; 77: 336–351. https://doi.org/10.1016/j.ijheatfluidflow.2019.05.004
38.
HandMSimmsDFingershL, et al.Unsteady aerodynamics experiment phase VI: wind tunnel test configurations and available data campaigns. National Renewable Energy Laboratory, 2001. Technical Report NREL/TP-500-29955. https://doi.org/10.2172/15000240
39.
SørensenNNMichelsenJASchreekS. Navier-stokes predictions of the NREL phase VI rotor in the NASA Ames 80-By-120 wind tunnel. Reno, Nevada, USA. ASME 2002 Wind Energy Symposium WIND2002-31. American Institute of Aeronautics and Astronautics, 2002, pp. 94–105. https://doi.org/10.1115/WIND2002-31
40.
WangYLiGShengS, et al.Investigation on aerodynamic performance of horizontal axis wind turbine by setting micro-cylinder in front of the blade leading edge. Energy2018; 143: 1107–1124. https://doi.org/10.1016/j.energy.2017.10.094
41.
JiangRZhaoZLiuY, et al.Effect of vortex generator orientation on wind turbines considering the three-dimensional rotational effect. Ocean Eng2023; 267: 113307. https://doi.org/10.1016/j.oceaneng.2022.113307
42.
HuHLuBLuoD, et al.CFD analysis of different leading edge tubercles on the aerodynamic performance of NREL phase VI wind turbine blades. Energy2025; 334: 137721. https://doi.org/10.1016/j.energy.2025.137721
