An experimental study of dynamic stall on a finite wing

Coton, F. N.; Galbraith, R.A.McD.

doi:10.1017/s0001924000027895

Cited by 42 publications

(23 citation statements)

References 7 publications

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“…Yilmaz & Rockwell [38] experimentally studied a 3D pitch-up wing and found a spanwise velocity induced by tip vortices altered the LEV development. This phenomenon was also seen in Coton & Galbraith [36] and Spentzos et al [37].…”

supporting

confidence: 64%

“…[29,32] For a dynamic stall problem, high Reynolds number (Re > 10 6 ) 3D experiments have been conducted by Piziali [33] and Tang & Dowell [34] for helicopter applications, but low Reynolds number (Re ≈ 10 3 −10 4 ) 3D experiments and simulations are sparse. [35,36,37,8,30,38] Since MAVs employ low aspect ratio wings, in order for the dynamic stall research to be applicable to MAVs, dynamic stall must be investigated as a 3D problem at low…”

mentioning

confidence: 99%

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Numerical study of leading edge vortex circulation development on finite aspect ratio perching wings.

Hord¹

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ACKNOWLEDGEMENTSMy deepest gratitude goes to the following individuals for making this dissertation possible.Yongsheng Lian for providing the opportunity to pursue my Ph.D even when there was no funding available. Finding support was a perpetual struggle, but he always was able to find it. He also had constant patience with me investing time into other projects unrelated to my research. The perching maneuver of natural fliers is a complex motion involving fast change of angle of attack, complicated wing kinematics, large wing deformation and agile body motion control, but the prominent aerodynamic features can be revealed using a simple pitch-up wing motion coupled with a stream wise deceleration. In this dissertation the aerodynamic forces, the leading edge vorterx (LEV) development, and LEV circulation of pitch-up and perching wings are extensively studied at low Reynolds number conditions. 2D and 3D wings of different aspect ratios were linearly pitched up from 0 • to 90• at three reduced pitch rates. The numerical investigation was conducted at a Reynolds number of 500 and the flow field was described using the unsteady three-dimensional incompressible Navier-Stokes equations on a set of composite overlapping grids. The Q-criterion was used to identify and isolate the LEV structure from shear layer vorticity. Results have shown that the LEV circulation depends primarily on the wing aspect ratio: increasing wing aspect ratio increased the rate of LEV circulation generation during the pitch-up motion. The reduced pitch rate for the pitch-up motion was found to delay the LEV circulation development when the aspect ratio was greater than two. For perching, pitch rate only altered the LEV propagation away from the wing, and not the magnitude of the circulation.iv

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supporting

confidence: 64%

mentioning

confidence: 99%

Numerical study of leading edge vortex circulation development on finite aspect ratio perching wings.

Hord¹

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“…The literature survey also reveals that very few experimental works (Piziali, 1994;Berton et al, 2003;Coton and Galbraith, 1999) have been conducted on wings of low and moderate aspect ratio, which are closer to modern rotor blades. Moreover, experiments mainly concern flow visualizations using micro tufts and pressure surface measurements (Piziali, 1994;Spentzos et al, 2007) and databases including both local velocity profiles, surface pressure, and overall forces measurements are rather rare (Berton et al, 2001(Berton et al, , 2003.…”

Section: Dynamic Stall In 2d/3d Unsteady Flow Configurationsmentioning

confidence: 99%

The Role of Wind Tunnel Experiments inCFDValidation

Favier

2010

Encyclopedia of Aerospace Engineering

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An attempt to answer the question of the current and future role of wind tunnel experiments in CFD validation is derived by using a selection of typical examples of suited experiments in the field of unsteady aerodynamics at subsonic flow regimes. Such examples concern 2D/3D flows over airfoils, cylinders, as well as tapered wings, and illustrate the three‐folded role of experiments. The three folds consist in providing a detailed description of the physics of complex flow phenomena, constituting reliable databases, and establishing reference comparisons for the CFD validation, both on global and local aerodynamic fields. Some points of interest, for instance integrating the use of wind tunnel experiments and CFD approaches, are also discussed including the evaluation of uncertainties in experimental and numerical results and requirements to yield efficient experimental databases.

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“…This is particularly the case at the top of the pitch cycle where much of the dynamic content of the response occurs within a relatively small incidence range. The evolution of the stall and the re-establishment of fully attached flow after stall can be better examined using linear ramp motions, ramp-up and ramp-down, that consider the two effects independently 28 . Data from such tests are currently under analysis.…”

Section: CMmentioning

confidence: 99%