Experimental Investigation into the Effect of Gurney Flaps on Various Airfoils

Cole, Julia A.; Vieira, Bernardo; Coder, James G.; Premi, Amandeep; Maughmer, Mark D.

doi:10.2514/1.c032203

Cited by 47 publications

(23 citation statements)

References 19 publications

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“…Additionally, they investigated the effect of chordwise positioning of the GF, showing that increased upstream positioning enlarges the hysteresis loop, degrades the lift enhancement, increases drag, and decreases the nose-down pitching moment. Similar limits were found also in [10,14,28,29]. Matalanis et al [30] carried out two-and three-dimensional simulations, together with experimental measurements, on a VR-12 section equipped with a deployable GF.…”

supporting

confidence: 50%

“…Cole et al [29] showed that, for some specific configurations and for angles of attack in the range 5 10 deg, lower drag coefficients could be attained with a GF. The reverse was found by employing other airfoil-GF configurations, leading Cole et al to conclude that the performance and effectiveness of a GF is dependent on the shape of the movable device and of the clean airfoil that is used.…”

Section: A Steady-state Numerical Simulationsmentioning

confidence: 98%

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Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Motta

Quaranta

2015

Journal of Aircraft

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Analysis of ballistic capture orbits in Sun–planet systems is conducted in this paper. This mechanism utilizes purely gravitational forces, and may occur in non-Keplerian regimes. Ballistic capture orbits are generated by proper manipulation of sets of initial conditions that satisfy a simple definition of stability. Six Sun–planet systems are considered, including the inner planets, Jupiter, and Saturn. The role of planets orbital eccentricity, their true anomaly, and mass ratios is investigated. Moreover, the influence of the post-capture orbit in terms of inclination and orientation is also assessed. Analyses are performed from qualitative and quantitative perspective. The quality of capture orbits is measured by means of the stability index, whereas the capture ratio gives information on their statistical occurrence. Some underlying principles on the selection of the dynamical model, the initial true anomaly, and inclination are obtained. These provide a reference for practical cases

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supporting

confidence: 50%

Section: A Steady-state Numerical Simulationsmentioning

confidence: 98%

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Motta

Quaranta

2015

Journal of Aircraft

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“…This concept has the additional advantage of locating the GF on the trailing edge, therefore maximizing its performance as shown in Refs. [10,14,[27][28][29]. Experimental measurements carried out by Zanotti et al [35,36] showed that this novel L-shaped tab could be exploited both downward deployed, as a GF, and upward deflected, as a classical TE flap, to mitigate the negative effects of dynamic stall.…”

Section: Introductionmentioning

confidence: 96%

“…Similar limits were found also in Refs. [10,14,28,29]. Matalanis et al [30] carried out 2D and 3D simulations, together with experimental measurements, on a VR-12 section equipped with a deployable GF.…”

Section: Introductionmentioning

confidence: 99%

Active Control on Helicopter Blades with a L-Shaped Gurney Flap

Motta

Quaranta

2015

56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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This work concerns an assessment of the rotor blade vibration reduction capabilities of a novel L-shaped trailing edge Gurney Flap. Previous numerical and experimental works highlighted how such device is potentially suitable for performance enhancement and stall alleviation on rotorcraft. Moreover, these studies showed that the primary effect of this L-tab is represented by a modification of the reference airfoil mean line shape, both in terms of camber and chord length, this latter being related to the two counter rotating vertical structures developed past the tab vertical prong. Previously validated computational uid dynamics results are exploited to develop a physically based thin-line reduced order model, which successfully reproduces the mean line modifications induced by the L-tab, in addition to accurately capture the steady aerodynamic forces and the first harmonic of the unsteady loads generated by fixed configurations of the airfoil L-tab system and by oscillating motionsof the movable device, respectively. A similar thin-line linear model is also developed for a blade section equipped with a classical trailing edge ap. Comparisons of the aerodynamic loads generated by these two movable devices for equal input oscillating laws allow to estimate the ranges of reduced frequency where the L-tab is expected to perform better with respect to the trailing edge ap and vice-versa. These two reduced order models are then exploited to build up two separate three degrees of freedom linear aerostructural models for a blade equipped with a partial span L-tab or trailing edge ap. A higher harmonic control algorithm is then applied and compared between the two devices to reduce separately the 2/rev, 3/rev, 4/rev and 5/rev harmonics of the blade root rotating frame vertical force, apping and feathering moments. A significant reduction of the vibratory loads is obtained. Moreover, the attainment of similar results with a well known trailing edge device, such the classical ap taken under consideration, is a further confirmation of the potential feasibility of this novel L-tab as an effective alternative mean for vibration reduction on rotor blades

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“…Circulation control and Gurney flap methods have been extensively investigated both experimentally 8,9 and numerically 10,11 over many years to enhance wing lift and alleviate dynamic stall. In the circulation control method, a small amount of high-velocity jet injects into main flow tangentially over a highly curved surface, such as a rounded trailing edge.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the S809 airfoil aerodynamic performance using a co-flow jet active control concept

Xing

2015

Journal of Renewable and Sustainable Energy

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A Co-Flow Jet (CFJ) active flow control concept is implemented on the S809 airfoil and numerically investigated by using an in-house code based on Reynoldsaveraged Navier-Stokes equations and the Spalart-Allmaras turbulence model, aiming to systematically study the jet effect on the airfoil aerodynamic performance. The solver is validated by comparing the computed results with the baseline experiment measurement. The calculated aerodynamic force and moment coefficients agree fairly well with the experimental data, demonstrating the present solver can predict the attached as well as separated flows around the S809 airfoil with an acceptable precision. The CFJ jet-off geometry of S809 airfoil is simulated to study the jet channel effect on the baseline aerodynamic characteristic, showing that the jet channel could reduce the lift, increase the drag and cause an earlier abrupt stall at angle of attack (AoA) 16.24 . The CFJ jet-on geometry is elaborately studied at three jet momentum coefficient levels, showing that co-flow jet has a significantly positive effect in increasing lift, stall margin, and drag reduction. For the cases with jet momentum coefficients 0.12 and 0.18, the total drag even becomes negative. It is found that the drag from pressure and shear stress of CFJ airfoil is larger than that of baseline, and it is the negative mass-flow-produced drag that significantly reduces the total drag to be below zero. For cases in which AoA are below a critical value (e.g., 20.15 for the case with jet momentum coefficient 0.18), the power required to drive the jet flow decreases when AoA increases, demonstrating that the CFJ concept has an attractive advantage of minimum energy consuming. The present CFJ concept is proved to be a promising and effective active flow control method in the wind turbine application. V C 2015 AIP Publishing LLC.

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Experimental Investigation into the Effect of Gurney Flaps on Various Airfoils

Cited by 47 publications

References 19 publications

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Active Control on Helicopter Blades with a L-Shaped Gurney Flap

Numerical study of the S809 airfoil aerodynamic performance using a co-flow jet active control concept

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