Control of leading-edge vortices on a delta wing

Magness, C.; Robinson, Owen; Rockwell, D.

doi:10.2514/6.1989-999

Cited by 39 publications

(10 citation statements)

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“…5.2d) are found to be in reasonable agreement with each other. The computed onset of vortex breakdown occurred for Grid I when a was increased from 31" to 32", whereas for Grid 2, it took place between 30" and 31", in closer agreement with experiment (Magness, 1991). The process by which breakdown appeared in the near-wake and moved over the wing was also found to be qualitatively similar for both grids.…”

Section: Resultssupporting

confidence: 72%

“…Vortex breakdown is still induced transiently above the wing but it eventually moves into the wake, albeit at very low speed. The behavior computed on Grid 2 is in agreement with the experiments of Magness (1991). In the these experiments it is found that when the wing is pitched at a high rate from a = 5" to a = 30" (below a=,.…”

Section: Gridsupporting

confidence: 78%

“…According to the experiments of Magness (1991), vortex breakdown moves upstream over the delta wing when the angle of attack is slowly increased (i.e. in a quasistatic manner) beyond a critical value a,, M 30.7'.…”

Section: Resultsmentioning

confidence: 99%

“…The sweep angle and Reynolds number were selected to permit comparison with the extensive experiments of Magness (1991).…”

Section: Flow Configuration Governing Equations and Numerical Proceduresmentioning

confidence: 99%

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On spurious behavior of CFD simulations

Yee

Torczynski

Morton

et al. 1997

13th Computational Fluid Dynamics Conference

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Spurious behavior in underresolved grids and/or semi-implicit temporal discretizations for four computational fluid dynamics (CFD) simulations are studied. The numerical simulations consist of (a) a 1-D chemically relaxed nonequilibrium model, (b) the direct numerical simulation (DNS) of 2-D incompressible flow over a backward facing step, (c) a loosely-coupled approach for a 2-D fluid-structure interaction, and (d) a 3-D compressible unsteady flow simulation of vortex breakdown in delta wings. Using knowledge from dynamical systems theory, various types of spurious behaviors that are numerical artifacts were systematically identified. These studies revealed the various possible dangers of misinterpreting numerical simulation of realistic complex flows that are constrained by the available computing power. In large scale computations underresolved grids, semi-implicit procedures, loosely-coupled implicit procedures, and insufficiently long time integration in DNS are most often unavoidable. Consequently, care must be taken in both computation and in interpretation of the numerical data. The results presented confirm the important role that dynamical systems theory can play in the understanding of the nonlinear behavior of numerical algorithms and in aiding the identification of the sources of numerical uncertainties in CFD.

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Section: Resultssupporting

confidence: 72%

Section: Gridsupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

“…The sweep angle and Reynolds number were selected to permit comparison with the extensive experiments of Magness (1991).…”

Section: Flow Configuration Governing Equations and Numerical Proceduresmentioning

confidence: 99%

See 2 more Smart Citations

On spurious behavior of CFD simulations

Yee

Torczynski

Morton

et al. 1997

13th Computational Fluid Dynamics Conference

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“…7 In the event that the delta wing undergoes unsteady motion, the nature of the vortex breakdown is altered. The most predominant feature is a phase shift between the motion of the wing and the onset of breakdown, as shown by Woffelt, 8 Gilliam et al, 9 Reynolds and Abtahi, 10 Hudson et al, 11 Thompson, 12 Magness et al, 13 Atta and Rockwell, 14 LeMay et al, 15 Jarrah, 16 Ashley et al, 17 and Rockwell;18 all of the foregoing investigations have been for pitching motion. Analogous types of phase shift of breakdown occur for rolling motion of the wing as shown by Hanff and Huang, 19 Ng et al, 20 and Cipolla et al 21 Conceptual features of the complex nature of vortex breakdown, interpreted in the context of experiments, theory, and numerical simulations are provided by the reviews and assessments of Sarpkaya, [22][23][24] Hall,25 Liebovich, 26,27 Escudier, 28 Brown and Lopez, 29 Lopez and Perry, 30 Delery, 31 and Wang and Rusak.…”

Section: Introductionmentioning

confidence: 90%

Control of vortex breakdown by a transversely oriented wire

2001

Self Cite

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A small wire oriented orthogonally to the axis of the leading-edge vortex on a delta wing at high angle of attack generates substantial changes in the vortex structure, which is characterized using a technique of high-image-density particle image velocimetry. A wire having a diameter two orders of magnitude smaller than the diameter of the leading-edge vortex prior to the onset of vortex breakdown can substantially advance the onset of breakdown by as much as 15 vortex diameters. Depending upon the dimensionless diameter of the wire and wire location along the axis of the vortex, the onset of vortex breakdown can occur either upstream or downstream of the wire. Contours of constant velocity indicate that the rate of decrease of streamwise velocity along the centerline of the vortex is substantially enhanced, even for locations well upstream of the wire, relative to the case of vortex breakdown in the absence of a wire. Patterns of instantaneous vorticity in the presence of the wire typically exhibit a form characteristic of either a spiral- or bubble-like mode of breakdown that occurs in the absence of the wire.

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Flow Visualization of the Leading Edge Vortices on Slender Wings Undergoing Large Amplitude Unsteady Motions

Nelson

Thompson

1992

Flow Visualization VI

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Control of leading-edge vortices on a delta wing

Cited by 39 publications

References 0 publications

On spurious behavior of CFD simulations

On spurious behavior of CFD simulations

Control of vortex breakdown by a transversely oriented wire

Flow Visualization of the Leading Edge Vortices on Slender Wings Undergoing Large Amplitude Unsteady Motions

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