Flow Structure on a Delta Wing of Low Sweep Angle

Yanıktepe, Bülent; Rockwell, D.

doi:10.2514/1.1207

Cited by 91 publications

(44 citation statements)

References 16 publications

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“…15a, a second, weaker vortical structure of the same sign as the primary vortex is seen outboard toward the leading edge. Similar dual vortex structures have been observed in previous computations [15] and experiments [12,14] and arise from the interaction of the secondary flow with the primary shear layer separating from the leading edge. As the secondary flow weakens with increasing Reynolds number, this interaction is reduced and the dual primary vortex structure is less pronounced.…”

Section: B Mean Vortex Structure In Crossflow Planes Normal To the Vsupporting

confidence: 59%

“…On each mesh, primary, secondary, and tertiary vortices are observed, as well as a second vortex of the same sign as the primary vortex outboard near the leading edge. This type of dual vortex system has been observed previously for low-sweep delta wings [12,14,15] and results from the interaction of the secondary flow with the primary shear layer. Increased unsteadiness resulting in significantly higher levels of turbulent kinetic energy is obtained with refinement, Fig.…”

Section: Grid Resolution Studymentioning

confidence: 74%

“…In recent years, a concerted effort has been made both experimentally [11][12][13][14] and computationally [15] to understand the distinctive characteristics of low-sweep delta wing flows. These investigations have primarily been performed at low Reynolds numbers (<40; 000).…”

Section: Introductionmentioning

confidence: 99%

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Computational and Experimental Investigation of a Nonslender Delta Wing

Gordnier¹,

Visbal²,

Gursul³

et al. 2009

AIAA Journal

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Computational simulations have been performed for a 50-deg-sweep delta wing with a sharp leading edge at a 15 deg angle of attack and moderate Reynolds numbers of Re 2 10 5 , Re 6:2 10 5 , and Re 2 10 6 . A sixthorder compact-difference scheme with an eighth-order low-pass filter is used to solve the Navier-Stokes equations. Turbulence modeling has been accomplished using an implicit large eddy simulation method that exploits the highorder accuracy of the compact-difference scheme and uses the discriminating higher-order filter to regularize the solution. Computations have been performed on a baseline mesh of 11:3 10 6 grid points and a refined mesh of 35 10 6 grid points. An assessment of grid resolution showed that significantly finer-scale features of the flow could be captured on the refined mesh, providing a more accurate representation of the complex, unsteady, separated flow. Comparisons are also made with high-resolution particle image velocimetry images obtained for the two lower Reynolds numbers. The numerical results are examined to provide a description of the mean and instantaneous flow structure over the delta wing, including the separated vortical flow, vortex breakdown, surface flow features, and surface boundary-layer transition near the symmetry plane. The effect of Reynolds number on each of these features is assessed.

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Section: B Mean Vortex Structure In Crossflow Planes Normal To the Vsupporting

confidence: 59%

Section: Grid Resolution Studymentioning

confidence: 74%

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Computational and Experimental Investigation of a Nonslender Delta Wing

Gordnier¹,

Visbal²,

Gursul³

et al. 2009

AIAA Journal

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“…It is expected, on the basis of investigations of a simple delta wing by Yaniktepe and Rockwell, 8 that an elongated layer of vorticity will form adjacent to the wing. The possibility, however, of a highly concentrated region of vorticity at the leading edge, which can be associated with the abrupt transformation of sweep angle, has not been addressed.…”

Section: Crossflow Topology On Diamond and Lambda Planformsmentioning

confidence: 98%

Flow Structure on Diamond and Lambda Planforms: Trailing-Edge Region

Yanıktepe

Rockwell

2005

AIAA Journal

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The instantaneous and averaged flow structure on diamond and lambda planforms is characterized by using a technique of high-image-density particle image velocimetry. Emphasis is on the structure in the trailing-edge region, over a range of angle of attack. Elongated layers of vorticity in the crossflow plane exhibit well-defined mean (time-averaged) and instantaneous concentrations of vorticity. These features are interpreted in conjunction with patterns of streamline topology, as well as images of rms velocity fluctuation and velocity spectra obtained from space-time imaging. NomenclatureC = root chord of entire planform, mm C = root chord of leading (delta-wing) portion of planform, mm f = frequency, Hz S = local semispan of wing, mm S w = spectrum of w component of velocity fluctuation U = freestream velocity, mm/s V = magnitude of velocity vector, mm/s v = instantaneous velocity fluctuation in direction parallel to surface of wing, mm/s w = instantaneous velocity fluctuation normal to surface of wing, mm/s w rms = rms of velocity fluctuation, mm/s x = distance from apex measured along plane of symmetry of wing, mm y = distance measured normal to plane of symmetry of wing, mm α = angle of attack, deg = sweep angle, deg ψ = stream function, mm 2 /s ω = vorticity, 1/s = time-averaged value of quantity

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“…Boundary layer separation causes these vortical structures formed by rolling up of viscous flow sheet. This flow separation mechanism is occurred due to angle of attack and sharp leading edges of the delta wing [3][4]. These vortices could not maintain their strength along their central axes and vortex breakdown is occurred at a certain distance from delta wing apex when angle of attack is increased slightly [5].…”

Section: Introductionmentioning

confidence: 99%

Aerodynamics and Flow Characteristics of X-45 Delta Wing Planform

Yanıktepe¹,

Özalp²,

Canpolat³

2016

KSU J. Eng. Sci.

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ABSTRACT:The present experimental work investigates the near surface flow structure and aerodynamic characteristics of X-45 type non-slender delta wing planform using dye visualization, Stereoscopic Particle Image Velocimetry (stereo-PIV) and aerodynamic load measurements. The instantaneous images are acquired on the planview plane within 5 o ≤ α ≤ 20 o to calculate the time-averaged flow data. In order to compare flow structures with other non-slender wing planforms such as delta and lambda, previously presented dye visualization and stereo-PIV results are also provided. It can be concluded that vortical flow with a pair of well-defined LEVs over X-45 develop at very low angles of attack, and form close to the wing surface similar to delta and lambda planforms. The stall occurs at an angle of attack α = 32 o , whereas stalling is evident at relatively lower angles of attack for simple delta wing. Keywords: Aerodynamics, delta wing, stereo-PIV, X-45 X-45 Tipi Delta Kanat Modeli Üzerinde Oluşan Akış Karakteristikleri ve AerodinamiğiÖZET: Mevcut deneysel çalışma ile X-45 tipi delta kanat modeli üzerinde oluşan yakın yüzey akış yapısı ve aerodinamik karakteristikleri, boya görüntüleme, üç boyutlu Stereoskopik Parçacık Görüntüleme Tekniği (stereo PIV) ve aerodinamik kuvvet ölçümleri kullanılarak araştırılmıştır. Anlık görüntüler ile üst görünüş düzleminde zaman ortalama akış verileri 5 o ≤ α ≤ 20 o hücum açılarında elde edilmiştir. Delta ve Lamda tipi diğer düşük süpürme açılarına sahip delta kanat modelleri ile akış yapılarını karşılaştırmak için önceki sunulan boya görüntüleri ve stero-PIV sonuçları kullanılmıştır. Düşük hücum açılarında X-45 tipi delta kanat modeli üzerinde iyi tanımlanmış ön uç yanal girdaplar delta ve lamda modellerine benzer kanat yüzeyinde oluşmaktadır. X-45 tipi delta kanat modelinde ölü akış yapısı α = 32 o de oluşmaktayken basit delta kanat ve lamda modellerinde daha düşük hücum açılarında meydana gelmektedir.

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Flow Structure on a Delta Wing of Low Sweep Angle

Cited by 91 publications

References 16 publications

Computational and Experimental Investigation of a Nonslender Delta Wing

Computational and Experimental Investigation of a Nonslender Delta Wing

Flow Structure on Diamond and Lambda Planforms: Trailing-Edge Region

Aerodynamics and Flow Characteristics of X-45 Delta Wing Planform

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