Numerical investigation into energy extraction of flapping airfoil with Gurney flaps

Xie, Yonghui; Jiang, Wenxue; Lu, Kun; Zhang, Di

doi:10.1016/j.energy.2016.05.039

Cited by 67 publications

(30 citation statements)

References 22 publications

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“…They observed that the net power extraction efficiency of the flexible tail was higher than the rigid tail. Then, Xie et al (2016) have numerically explored the effects of the gurney flap on the energy extraction performances of flapping airfoil. Their results revealed that, compared to a standard NACA0012 flapping airfoil, the use of optimized gurney flap led to a significant increase of the output power coefficient and the energy extraction efficiency.…”

Section: Intoductionmentioning

confidence: 99%

“…These results are consistent with those of (Fertis 1994, Boroomand and Hosseinverdi 2009, Kamyab et al 2016and Kamyab and Ghassemi 2017 in which it was concluded that the stepped foil can improve the lift coefficient and the lift to drag ratio with a little increase of the drag coefficient. Xie et al(2016) noted that in the field of energy extraction by flapping foil, more attention is focused to the lift improvement, while the drag penalty can be offset by the structural amelioration. Therefore, the main differences in forces and moment distribution are attributed to the change in flow structure around the foil caused by the geometric modification.…”

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confidence: 99%

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Energy Extraction Performance Improvement of a Flapping Foil by the Use of Combined Foil

Boudis

Boutarfaïa

Oualli

et al. 2018

JAFM

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In this study, numerical investigations on the energy extraction performance of a flapping foil device are carried out by using a modified foil shape. The new foil shape is designed by combining the thick leading edge of NACA0012 foil and the thin trailing edge of NACA0006 foil. The numerical simulations are based on the solution of the unsteady and incompressible Navier-Stokes equations that govern the fluid flow around the flapping foil. These equations are resolved in a two-dimensional domain with a dynamic mesh technique using the CFD software ANSYS Fluent 16. A User Define Function (UDF) controls the imposed sinusoidal heaving and pitching motions. First, for a validation study, numerical simulations are performed for a NACA0012 foil undergoing imposed heaving and pitching motions at a low Reynolds number. The obtained results are in good agreement with numerical and experimental data available in the literature. Thereafter, the computations are applied for the new foil shape. The influences of the connecting area location between the leading and trailing segments, the Strouhal number and the effective angle of attack on the energy extraction performance are investigated at low Reynolds number (Re = 10 000). Then, the new foil shape performance was compared to those of both NACA0006 and NACA0012 baseline foils. The results have shown that the proposed foil shape achieves higher performance compared to the baseline NACA foils. Moreover, the energy extraction efficiency was improved by 30.60% compared to NACA0006 and by 17.32% compared to NACA0012. The analysis of the flow field around the flapping foils indicates a change of the vortex structure and the pressure distribution near the trailing edge of the combined foil compared to the baseline foils.

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Section: Intoductionmentioning

confidence: 99%

mentioning

confidence: 99%

Energy Extraction Performance Improvement of a Flapping Foil by the Use of Combined Foil

Boudis

Boutarfaïa

Oualli

et al. 2018

JAFM

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“…In the domain of aerospace and aviation, the existence of flow separation leads to the instability of flying vehicles, the generation of noise, increasing the drag and decreasing the lift. The flow separation control technology has been gradually developed as an important branch of mechanics [6][7][8]. Traditionally, passive [7][8][9] or active [10][11][12][13] devices are used for flow separation control.…”

Section: Introductionmentioning

confidence: 99%

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Fatahian

Nichkoohi

Salarian

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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In the present study, the effect of hinge position (H) has been numerically investigated to find the appropriate position for improving the aerodynamic performance of the NACA 0012 flapped airfoil. In addition, perpendicular and tangential suctions have been applied to control the flow separation and enhance the aerodynamic performance over the NACA 0012 flapped airfoil at each different hinge positions. The simulations were carried out at a Reynolds number of 5 × 10 5 (Ma = 0.021) based on two-dimensional incompressible unsteady Reynolds-averaged Navier-Stokes calculations to determine the adequate hinge position. The turbulence was modeled using the shear stress transport k-ω turbulence model. The effect of perpendicular suction (θ jet = − 90°) and tangential suction (θ jet = − 30°) was computationally studied over NACA 0012 flapped airfoil for five different hinge positions (H = 0.7c, 0.75c, 0.8c, 0.85c and 0.9c) and a flap deflection (δ f) of 15°. Based on the results, the hinge position significantly affects the aerodynamic performance of the airfoil. The lift coefficient increased clearly as the hinge position moved to the trailing edge of the airfoil. Using perpendicular suction caused to increase the lift coefficient and decrease the drag coefficient. Consequently, the maximum value of the lift-to-drag ratio (C L /C D) for perpendicular and tangential suctions was achieved about 35.8% and 25.1% higher than that of the case without suction at an angle of attack of 12° and H = 0.9c. Also, the effect of perpendicular suction was more considerable compared to the tangential suction. This caused a reduction in the size of the recirculation zone from 0.5 to 0.09 of the airfoil chord length and also transferred it from 1.13 to 1.18 of the airfoil chord length.

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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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Numerical investigation into energy extraction of flapping airfoil with Gurney flaps

Cited by 67 publications

References 22 publications

Energy Extraction Performance Improvement of a Flapping Foil by the Use of Combined Foil

Energy Extraction Performance Improvement of a Flapping Foil by the Use of Combined Foil

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Effect of Gurney Flap Geometry on a S809 Airfoil

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