Trailing vortex detection and quantitative evaluation of vortex characteristics by PIV technique

Albano, F.; Gregorio, F. De; Ragni, A.

doi:10.1109/iciasf.2003.1274850

Cited by 3 publications

(4 citation statements)

References 11 publications

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“…Vortical Structure. Albano et al [12] and Chow et al [16] proposed the crossflow velocity (U c = ffiffiffiffiffiffiffiffiffiffiffiffiffi ffi u 2 + v 2 p , u, and v are the stream-wise velocity and the normal velocity, respectively) to describe the rolling up of the wingtip vortex. As shown in Figure 16, crossflow velocity around the wingtip of the baseline and control shows that the lateral flow near the secondary vortex is significantly enhanced but the lateral flow near the primary vortex is restrained.…”

Section: Control Effect Of Normal Blowingmentioning

confidence: 99%

“…This three-dimensional effect is strongest near the wingtip, i.e., the wingtip vortex. Based on the characteristics of the flow field, Albano et al [12] proposed a spatial division on the evolution of a wingtip vortex: the form-field, near-field, and farfield regions. Many studies have been carried out through experiments and numerical simulations [13][14][15][16][17][18] on the formation of a wingtip vortex and the flow structure at the near-field region.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Normal Blowing Approach to Controlling Wingtip Vortex Using LES

Jiang

Wang

Qin

et al. 2021

International Journal of Aerospace Engineering

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The characteristics and control of a wingtip vortex are of great significance when considering drag reduction and flight safety of transportation aircrafts. The associated aerodynamic phenomenon resulting from rolling up of a wingtip vortex includes boundary layer flow, shear layer separation, and vortex breakdown, while the interaction of a wingtip vortex with the airframe causes induced drag, wingtip noise, etc. This paper studies a normal blowing method utilized to control the wingtip vortex. Large eddy simulation (LES) technique applied to a straight NACA0012 wing having a chord length ( c ) of 0.4 m is adopted for this study. The Reynolds number based on the chord length is 1.6 × 10 6 and the angle of attack is 12°. The computational approach utilized the dynamic Smagorinsky-Lilly subgrid model for 3D simulations. Normal blowing from a high aspect ratio jet from the wingtip lower surface was used to control the wingtip vortex. From 0.05c to 0.30c, the blowing slit width was 1 mm, with the slit exit treated as a velocity inlet boundary condition which supplied the blowing jet with a momentum coefficient of 0.28%. Results of axial velocity and span-wise pressure distribution of the clean airfoil presented good agreement with known experimental data. LES results indicate that normal blowing suppresses the primary vortex strength, while the vortex core radius, maximum induced velocity, axial vorticity flux, and pressure peak of the primary vortex are reduced by 25%, 28%, 46%, and 52%, respectively. Flow field structures before and after blowing show that blowing suppresses the shedding, coiling, and convergence of the free vortex layers near the primary vortex. This study also shows that normal blowing generates a jet-induced vortex at the location of the secondary vortex, while backflow, volume expansion, and spiral burst can be observed in the jet-induced vortex. The bursting jet-induced vortex destroys the jet-like flow structure of the primary vortex at the trailing edge.

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Section: Control Effect Of Normal Blowingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of the Normal Blowing Approach to Controlling Wingtip Vortex Using LES

Jiang

Wang

Qin

et al. 2021

International Journal of Aerospace Engineering

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“…As discussed in Refs. [38]- [40], the evolution of the vortices in the wake of an aircraft can be divided into the following zones: -the near field, usually no more than one wing span downstream, in which several smaller vortices spring off the wing tips, edges of flaps, wing-fuselage junctions, and so on, -the "extended" near field, typically up to 12 wing spans downstream, in which the smaller vortices merge into a pair of counter-rotating vortices, -the mid field, characterized by a steady condition of the vortex pair, and -the far field where the wake vortices become unstable and the decay of circulation sets in.…”

Section: Wake Vorticesmentioning

confidence: 99%

“…Merger of vortices behind transport aircraft models has been investigated both in long wind tunnel test sections [38][39][42]- [44] and towing tank facilities [40][45]- [47], to acknowledge just a few. Both passive devices, altering the circulation distribution, and active devices, promoting an earlier demise of the generated vortices, have been proposed.…”

Section: Wake Vorticesmentioning

confidence: 99%

The Vortex Merger Factor in Aircraft Wake Turbulence

Mokry¹

2005

Aeronaut. j.

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Vortex merger is studied within the context of twodimensional discrete vortex sheets and demonstrated on two equally oriented circular vortices and aircraft tip and flap vortices. It is confirmed that, depending on the wing load distribution, the latter may or may not coalesce into a single counter-rotating pair. The interaction of a vortex with an equally oriented shear layer, governed by the same physical principle, suggests a possible intensification of an aircraft vortex in cross-wind shear.

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