Airfoil flow control using vortex generators and a Gurney flap

Hao, Lishu; Gao, Chao; Song, Wenping; Song, Ke

doi:10.1177/0954406213478533

Cited by 7 publications

(3 citation statements)

References 12 publications

(12 reference statements)

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“…could provide an attractive choice for the root part of a wind turbine blade where reduction of solidity is a key issue to reduce blade costs." In a more recent study, Li-shu et al (2013) performed wind tunnel tests on a WA251A airfoil at the Northwestern Polytechnical University of Xi'an. Maximum lift was increased by 18.6 % delaying stall by approximately 2 • .…”

Section: Combining Vortex Generators and Gurney Flapsmentioning

confidence: 99%

Experimental investigation of mini Gurney flaps in combination with vortex generators for improved wind turbine blade performance

Alber¹,

Μανωλέσος

Weinzierl-Dlugosch³

et al. 2022

Wind Energ. Sci.

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Abstract. This wind tunnel study investigates the aerodynamic effects of mini Gurney flaps (MGFs) and their combination with vortex generators (VGs) on the performance of airfoils and wind turbine rotor blades. VGs are installed on the suction side aiming at stall delay and increased maximum lift. MGFs are thin angle profiles that are attached at the trailing edge in order to increase lift at pre-stall operation. The implementation of both these passive flow control devices is accompanied by a certain drag penalty. The wind tunnel tests are conducted at the Hermann-Föttinger Institut of the Technische Universität Berlin based on two airfoils that are characteristic of different sections of large rotor blades. Lift and drag are determined using a force balance and a wake rake, respectively, for static angles of attack between −5 and 17∘ at a Reynolds number of 1.5 million. The impact of different MGF heights including 0.25 %, 0.5 % and 1.0 % and a VG height of 1.1 % of the chord length is tested and evaluated. Furthermore, the clean and the tripped baseline cases are considered. In the latter, leading-edge transition is forced with Zig Zag (ZZ) turbulator tape. The preferred configurations are the smallest MGF on the NACA63(3)618 and the medium-sized MGF combined with VGs on the DU97W300. Next, the experimental lift and drag polar data are imported into the software QBlade in order to design a generic rotor blade. The blade performance is simulated with and without the add-ons by means of two case studies. In the first case, the retrofit application on an existing blade mitigates the adverse effects of the ZZ tape. Stall is delayed and the aerodynamic efficiency is partly recovered leading to an improvement of the power curve. In the second case, the new design application allows for the design of a more slender blade while maintaining the rotor power. This alternative blade appears to be more resistant against the adverse effects of forced leading-edge transition.

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Section: Combining Vortex Generators and Gurney Flapsmentioning

confidence: 99%

Experimental investigation of mini Gurney flaps in combination with vortex generators for improved wind turbine blade performance

Alber¹,

Μανωλέσος

Weinzierl-Dlugosch³

et al. 2022

Wind Energ. Sci.

View full text Add to dashboard Cite

show abstract

“…Besides, these results are in good agreement with comparable tests using the prior Riso-A1-24 airfoil design, as previously reported by Fuglsang et al (1999). In a more recent study, Li-shu et al (2013) performed experiments on the WA251A airfoil at the Northwestern Polytechnical University of Xi'an at Re = 3•10 6 . Applying hGF = 0.9 %c and 1.25 %c together with hVG = 0.5 %c at xVG = 21 %c, cl,max is increased by 18.6 % delaying stall by approximately 2°.…”

Section: Combining Vortex Generators and Gurney Flapsmentioning

confidence: 99%

Experimental investigation of Mini Gurney Flaps in combination with vortex generators for improved wind turbine blade performance

Alber

Μανωλέσος

Weinzierl-Dlugosch³

et al. 2021

Preprint

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Abstract. This wind tunnel study investigates the aerodynamic effects of Mini Gurney flaps (MGFs) and their combination with vortex generators (VGs) on the performance of airfoils and wind turbine rotor blades. VGs are installed on the suction side aiming at stall delay and increased maximum lift. MGFs are thin angle profiles that are attached at the trailing edge in order to increase lift at pre-stall operation. The implementation of both these passive flow control devices is accompanied by a certain drag penalty. The wind tunnel tests are conducted at the Hermann- Föttinger Institut of the Technische Universität Berlin. Lift is determined with a force balance and drag with a wake rake for static angles of attack from −5° to 17° at a constant Reynolds number of 1.5 million. The impact of different MGF heights including 0.25 %, 0.5 % and 1.0 % and an uniform VG height of 1.1 % of the chord length are tested on three airfoils that are characteristic for different sections of large rotor blades. Furthermore, the clean and the tripped baseline cases are considered. In the latter, leading edge transition is forced by means of Zig Zag (ZZ) turbulator tape. The preferred configurations are the smallest MGF on the NACA63(3)618 and the AH93W174 (mid to tip blade region) and the medium sized MGF combined with VGs on the DU97W300 (root to mid region). Next, the experimental lift and drag polar data is imported into the software QBlade in order to design a generic rotor blade. The blade performance is simulated with and without the add-ons based on two case studies. In the first case, the retrofit application on an existing blade mitigates the adverse effects of the ZZ tape. Stall is delayed and the aerodynamic efficiency is partly recovered leading to an improvement of the power curve. In the second case, the new design application allows for the design of a more slender blade while maintaining the power output. Moreover, the alternative blade appears to be more resistant against forced leading edge transition.

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“…Gurney flaps have been widely used and studied in airfoil static/dynamic stall control [2][3][4][5], flutter control [6], flapping airfoil control [7], ground effects [8], and rotor blade load control [9][10][11][12][13]. In these applications, the increases in the lift and the drag are closely related to airfoils, flow conditions, and the flap geometry.…”

Section: Introductionmentioning

confidence: 99%

Effect of Gurney Flap Geometry on a S809 Airfoil

Hao

Gao

2019

International Journal of Aerospace Engineering

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In this paper, the effect of Gurney flap shapes on wind turbine blade airfoil S809 has been studied by numerical simulation. First, the O-type grid is used in the numerical simulation. By comparing with experimental data, such as the lift force, the drag coefficient, and the pressure distribution, the accuracy of the simulation method is validated. Second, the research on the widths of three kinds of rectangular Gurney flaps at the trailing edge of the S809 airfoil is carried out. Rectangular Gurney flaps can considerably increase the lift in both the linear and nonlinear sections, and the maximum lift coefficient can be increased by 20.65%. In addition, the drag and the pitching moment are increased. However, the width of the rectangular Gurney flap has a small impact on the lift, the drag, and the pitching moment. Finally, the effects of rectangular and triangular Gurney flaps on the aerodynamic characteristics of the S809 airfoil are compared. The results show that the triangular flaps can obtain an increase of maximum lift coefficient by 28.42%, which is better than 16.31% of the rectangular flaps.

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Airfoil flow control using vortex generators and a Gurney flap

Cited by 7 publications

References 12 publications

Experimental investigation of mini Gurney flaps in combination with vortex generators for improved wind turbine blade performance

Experimental investigation of mini Gurney flaps in combination with vortex generators for improved wind turbine blade performance

Experimental investigation of Mini Gurney Flaps in combination with vortex generators for improved wind turbine blade performance

Effect of Gurney Flap Geometry on a S809 Airfoil

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