Exploratory Study of Aircraft Wake Vortex Filaments in a Water Tunnel

Rokhsaz, Kamran; Foster, Scott R.; Miller, L. Scott

doi:10.2514/2.2706

Cited by 23 publications

(10 citation statements)

References 9 publications

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“…Many researchers speculate that wandering is a consequence of either wind-tunnel effects (Corsiglia et al 1973;Devenport et al 1996;Beresh et al 2010) or a self-induced vortex instability (Rokhsaz et al 2000;Jacquin et al 2001). Wandering persists at zero angle of attack, indicating that it occurs despite the presence of a vortex (Baker et al 1974), which may suggest that the motion is independent of the vortex itself and may be a result of the wind-tunnel environment.…”

Section: Introductionmentioning

confidence: 99%

On the mechanism of trailing vortex wandering

et al. 2016

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The mechanism of trailing vortex wandering has long been debated and often attributed to either wind-tunnel effects or a self-induced instability. We remove the effect of wandering from a measured velocity field by averaging and, through a triple decomposition, recover the coherent wandering motion. Based on this wandering motion, the most energetic structures are computed using the proper orthogonal decomposition (POD) and exhibit a helical mode |m| = 1 whose kinetic energy grows with downstream progression. As such, we hypothesize that a vortex instability underlies the wandering motion, and test this hypothesis by performing a spatial stability analysis of a matched Batchelor vortex, which is devoid of wind-tunnel effects. The primary stability mode is marginally stable and is nearly identical, in size and structure, to the principal POD mode. The strikingly similar structure coupled with the measured energy growth supports the proposition that the vortex wandering is the result of an instability. The cause of the wandering is the non-zero radial velocity of the |m| = 1-mode on the vortex centerline, transversely displacing the trailing vortex as observed in experiments. However, the marginal nature of the stability mode prevents any conclusion regarding the specific type of instability.

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Section: Introductionmentioning

confidence: 99%

On the mechanism of trailing vortex wandering

et al. 2016

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“…They concluded that the vortex core in their experiments was laminar and that velocity fluctuations in the vortex core region were entirely due to wandering. Rokhsaz (2000) investigated wandering of a tip-vortex from a rectangular flat plate airfoil in a water tunnel and showed that wandering increased with angle of attack and therefore vortex strength, the opposite to the finding of Devenport et al (1996) who showed a 15% reduction in wandering amplitude with an increase in vortex strength of 85%.…”

Section: Introductionmentioning

confidence: 83%

“…The errors were larger for lower angles of attack. They also found that the wandering amplitude increases linearly with streamwise distance; a linear reduction was found by increasing the angle of attack, so that they concluded that the mechanism responsible for wandering is not self-induced, as had been proposed by Rokhsaz et al (2000), but rather that the vortex is responding to an external perturbation, as for instance the background turbulence level, to which the tip vortex becomes less susceptible as the vortex strength is increased.…”

Section: Introductionmentioning

confidence: 85%

“…And for the higher angles of attack, the wandering amplitude increases 50% with the 25% increase in vorticity. Rokhsaz (2000) and Devenport et al (1996) reported that wandering amplitude increases with increasing angle of attack and decreasing angle of attack, respectively; however, figure 4 shows that the wandering could increase or decrease with increasing angle of attack. ).…”

Section: Vortex Center Identificationmentioning

confidence: 99%

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A Stereoscopic PIV Study of a Near-Field Wingtip Vortex

Igarashi

Durbin

Ma³

et al. 2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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An experimental study was conducted to investigate the wing-tip vortex generated from a rectangular NACA0012 airfoil model. A high-resolution Stereoscopic Particle Image Velocimetry (SPIV) system was used to conduct detailed flow field measurements to quantify the transient behavior of the wing-tip vortex in the near field. The characteristics of the vortex wandering phenomena, i.e., the slow side-to-side movement of the wing-tip vortex core, were revealed in great detail based on the SPIV measurement results.

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“…They concluded that the vortex core in their experiments was laminar and that velocity fluctuations in the vortex core region were entirely due to wandering. Rokhsaz et al (2000) investigated wandering of a tip-vortex from a rectangular flat plate airfoil in a water tunnel and showed that wandering increased with angle of attack and therefore vortex strength, the opposite to the finding of Devenport et al (1996) who showed a 15% reduction in wandering amplitude with an increase in vortex strength of 85%.…”

Section: Overviewmentioning

confidence: 85%

A stereoscopic PIV study on the behavior of near-field wingtip vortex structures

Igarashi

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Exploratory Study of Aircraft Wake Vortex Filaments in a Water Tunnel

Cited by 23 publications

References 9 publications

On the mechanism of trailing vortex wandering

On the mechanism of trailing vortex wandering

A Stereoscopic PIV Study of a Near-Field Wingtip Vortex

A stereoscopic PIV study on the behavior of near-field wingtip vortex structures

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