On the Vortex Breakdown Phenomenon in High Angle of Attack Flows Over Delta Wing Geometries

Robertson, Eric D.; Chitta, Varun; Walters, D. Keith; Bhushan, Shanti

doi:10.1115/imece2014-39354

Cited by 7 publications

(7 citation statements)

References 12 publications

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“…Choudhury [15] also performed a preliminary study of flow over a delta wing at different angle of attack. Robertson et al [16] extended the above study, to elucidate the vortex breakdown phenomena over a delta wing using delayed DES (DDES) and k -ω SST models.…”

mentioning

confidence: 95%

“…Overall flow features, including an analysis of turbulent structures, are examined to understand the vortex breakdown phenomenon. The results have been presented in detail in[16], and are summarized here with key figures.Overall Vortical Structures and Vortex Breakdown Analysis.Flow predictions for both α = 18 and 23 show two primary vortices originating at the apex of the wing. The OpenFOAM show that the apex vortices expand steadily downstream, whereas the DDES predicts a bubble-like structure before descending into a spiral burst mode as shown inFig.…”

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confidence: 98%

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Validation of OpenFOAM numerical methods and turbulence models for incompressible bluff body flows

et al. 2015

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confidence: 95%

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confidence: 98%

Validation of OpenFOAM numerical methods and turbulence models for incompressible bluff body flows

et al. 2015

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“…reproducing the diffused vortex core and spiral vortex motion [23,24], contrary to what is reported by Robertson et al [22]. Figure 4 shows also that the vorticity produced by the separating shear layer over the leeward side of the DW leaves the trailing edge and creates a wake.…”

Section: B Sensitivity Analysismentioning

confidence: 61%

Vortex Flow and Aerodynamic Performance of a Reverse Delta Wing

Mahgoub

Cortelezzi

2020

AIAA Journal

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We simulate numerically the unsteady flow past a reverse delta wing to characterize the structure of the vortical flow and associated unsteady phenomena, and quantify the impact of such structures on the aerodynamic performance. We select the most cost-effective gridsize/time-step combination by performing a coupled sensitivity analysis. We successfully validate our numerical approach against well established results for a delta wing. We establish that the flow past a reverse delta wing is always unsteady even at small angles of attack. The shear layer separating at the leading edge of the reverse delta wing rolls-up into spanwise vortical structures that, as they are convected downstream, pair, realign and reorganize generating suction that contributes substantially to the lift produced by a reverse delta wing. The tip vortices confine the vortical structures to the leeward side and contribute to a less extent to lift. Power spectral density analysis shows that the unsteadiness of the lift coefficient is related

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“…However, the excessive increase of angle of attack induced unsteady flow, and this situation could cause a sudden collapse of the vortex flow, causing the strength to drop. This phenomenon is called vortex breakdown [14] similar to stall conditions on conventional wings. The vortex breakdown can reduce the aircraft longitudinal statics stability and lift force.…”

Section: Introductionmentioning

confidence: 97%

Tuft Flow Visualisation on UTM-LST VFE-2 Delta Wing Model Configuration at High Angle of Attacks

Said¹,

Imai²,

Mat³

et al. 2020

IJAME

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This paper reports on flow visualisation and surface pressure measurements over the upper surface of a blunt-edged delta wing model at high angles of attack. The flow structure above the upper surface of the blunt-edged delta wing was found to be different compared to delta wing with sharp leading edge. The flow becomes more complicated especially in the leading edge region of the wing. Currently, there is no data available to verify if the primary vortex could reach the apex of the wing when the angle of attack is further increased. Most prior experiments were performed at the angles of attack, α, below 23° with only a few experiments that had gone to α = 27°. These prior experiments and some CFD works stipulated that the attached flow continue to exist in the apex region of the delta wing even at very high angles of attack above 23°. In order to verify this hypothesis, several experiments at high angles of attack were conducted in Universiti Teknologi Malaysia Low Speed wind Tunnel (UTM–LST), using a specially constructed VFE2 wing model equipped with blunt leading edges. This series of experiments employed two measurement techniques; the first was the long tuft flow visualisation method, followed by surface pressure measurements. The experiments were performed at Reynolds numbers of 1.0×106 and 1.5×106. During these experiments, several interesting flow characteristics were observed at high angles of attack, mainly that the flow became more sensitive to changes in Reynolds number and the angles of attack of the wing. When the Reynolds number increased from 1×106 to 1.5×106, the upstream progression of the initial point of the main vortex was relatively delayed compared to the sharp-edged delta wing. The experiments also showed that the flow continued to be attached in the apex region up to α = 27º.

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On the Vortex Breakdown Phenomenon in High Angle of Attack Flows Over Delta Wing Geometries

Cited by 7 publications

References 12 publications

Validation of OpenFOAM numerical methods and turbulence models for incompressible bluff body flows

Validation of OpenFOAM numerical methods and turbulence models for incompressible bluff body flows

Vortex Flow and Aerodynamic Performance of a Reverse Delta Wing

Tuft Flow Visualisation on UTM-LST VFE-2 Delta Wing Model Configuration at High Angle of Attacks

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