The entrainment effect of a leading-edge vortex

Verhaagen, N.G.; Kruisbrink, Ach

doi:10.2514/6.1985-1584

Cited by 7 publications

(7 citation statements)

References 2 publications

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“…Inside the vortex core, Computed distributions of the circumferential velocity component versus radial distance from the vortex-core axis along y = yc over a flatplate delta wing, ǫ = 14 • , α = 20.4 • , with fine and coarse grids compared with theoretical solutions 27 and experimental data. 21 the vorticity increases sharply toward the core center and reaches a maximum value at the center. From Fig.…”

Section: B Numerical Solutionmentioning

confidence: 96%

“…In fact, the topics of the vortex core has been studied extensively. For example, Carcaillet, Manie, Pagan, and Solognac 20 and Verhaagen and Kruisbrink 21 by experimental methods, Murman and Rizzi, 22 Rizzi, 23 Powell, Murman, Perez and Baron, 24 Rizzetta and Shang 25 and Liu, Cai and Luo 26 by numerical methods, and Hall 27 and van Noordenburg and Hoeijmakers 28 by theoretical methods.…”

Section: Introductionmentioning

confidence: 99%

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Vortex Core and Its Effects on the Stability of Vortex Flow over Slender Conical Bodies

Luo

Liu

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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A three-dimensional Euler solver is used to study the vortex core over slender conical bodies at high angles of attack and low speeds. A three-dimensional conical overset-grid is established to reduce the computational efforts while accurately resolve the vortex flow. The numerical results on the vortex core are verified by available experimental data and theoretical solutions. The line vortex model used in the theoretical stability analyses made by the present authors for the vortex flow is modified to account for the effects of the vortex cores. The jetlike flow in the vortex core and inflow at its outer edge are modeled based on numerical experiments by the Euler methods on slender conical bodies incorporated with known theoretical and experimental results on vortex cores. Using the Euler solutions as a benchmark, the modified model yields a better predictions in the vortex positions than the original, and a favorable shifts of the transition point of stability in the Sychev similarity parameter.

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Section: B Numerical Solutionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Vortex Core and Its Effects on the Stability of Vortex Flow over Slender Conical Bodies

Luo

Liu

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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“…For the wing-alone model the asymmetric flow is well known. For example, Stahl et al 6 observed that the leading-edge vortices are symmetric, Verhaagen et al 14 using a no-nulling five-hole probe showed that the crossflow velocity components are conical away from the apex and trailing edge regions, and Visser, et al 15 showed that the axial vorticity is also conical by hot-wire measurements. Thus, only one station at x/c 0 = 0.6 is measured for the wing model, while for the wing-fin model a series of stations are studied.…”

Section: Experimental Results Review Of Piv Study At α = 30mentioning

confidence: 99%

Experimental Investigations on Stability of Vortex Flow over Slender Delta Wing with Dorsal Fin

Meng

Cai

Zhang

et al. 2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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A vortex stability theory for slender conical bodies developed by Cai, Liu, and Luo predicted that vortices over a flat-plate delta wing at high angles of attack with zero sideslip are conical, symmetric, and stable but adding a low dorsal fin to the wing would destabilize the vortices and therefore render the originally symmetric vortices asymmetric and/or nonconical. To verify the validity of the theoretical predictions and show the behaviors of the vortices over the slender delta wing and its combinations when the flowfield-asymmetry onset occurs, a 2-D Particle Image Velocimetry (PIV) study is presented in this paper. A sharp-edged flat-plate delta wing of 82.5 sweep angle is tested in a low-speed wind tunnel at angle of attack of 35 and zero sideslip. The PIV technique is used to visualize and measure the distributions of the vorticity component normal to the cross-flow plane at 60% wing root chord. The same test is performed on an identical delta wing model but with a flat plate dorsal fin mounted vertically in the incidence plane of the wing. Two fin heights are tested， the ratios of the local fin height to the local wing semi-span are 0.3 and 0.6 respectively. The PIV results indicate that the vortex pair is symmetric and steady over the wing, but vortex breakdown occurs periodically when adding the low dorsal fin. The results provide direct experimental evidence of the theoretical predictions.

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“…The pressure losses at the vortex core are largestdue to accumulatedviscous losses. 34 The large radial gradients evident in the pressure loss contours are a manifestation of misalignment between the vorticity and velocity vectors. This follows from Crocco's theorem assuming steady inviscid adiabatic ow.…”

Section: Flow Eld Propertiesmentioning

confidence: 98%

“…However, this is clearly not the case and is indicative of radial in ow velocities as a result of the low pressures experienced along the vortex core. 34 The center of the vortex is clearly visible as a white mark, indicating zero rotational velocity. The data do not show any marked effect of nonplanarity on the rotational velocity distribution.…”

Section: Flow Eld Propertiesmentioning

confidence: 99%

Effects of Anhedral and Dihedral on a 75-deg Sweep Delta Wing

Traub

2000

Journal of Aircraft

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An investigation into the effects of spanwise camber in the form of anhedral and dihedral on a 75-deg sweep delta wing is detailed. Data are presented encompassing force balance, surface pressure measurement, seven-hole probe surveys, and vortex burst trajectories. The results show that the net effect of this form of nonplanarity is an increase in lift for anhedral and a decrease in lift for dihedral compared to the planar wing. Small anhedral angles are most effective in augmenting lift. Anhedral does not appear to greatly augment the strength of the leading-edge vortex. The major bene t from anhedral would appear to be due to its displacing effect on the vortex trajectory: drawing the vortex closer to the wing surface and inboard compared to the planar wing. As the vortex is drawn inboard, its induced surface loading acts on a greater area of the wing. Dihedral also draws the vortex closer to the wing surface (to a greater extent then anhedral) while moving the vortex toward the wing leading edge. In addition, anhedral does not appear to introduce any detrimental effects on longitudinal stability and does not incur any penalties in terms of vortex burst characteristics. Nomenclature C D min = minimum drag coef cient C L = lift coef cient C N = normal force coef cient C pt = maximum stagnation pressure loss C T = leading-edge thrust coef cient c r = wing root chord k = wing ef ciency parameter k P = potential lift constant q = freestream dynamic pressure r = radial coordinate, measured from vortex center line s = local semispan U = freestream velocity V A = axial velocity V h = rotational velocity v, w = spanwise velocity, vertical velocity normal to wing surface x, y, z, y 0 , z 0 = Cartesian coordinates, y 0 and z 0 orientated at u a = wing centerline incidence C = vortex circulation K = wing leading-edge sweep angle u = wing dihedral angle, de ned (¡ ) for anhedral, (+ ) for dihedral x = axial vorticity Subscripts max = maximum min = minimum np = nonplanar pr = projected

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The entrainment effect of a leading-edge vortex

Cited by 7 publications

References 2 publications

Vortex Core and Its Effects on the Stability of Vortex Flow over Slender Conical Bodies

Vortex Core and Its Effects on the Stability of Vortex Flow over Slender Conical Bodies

Experimental Investigations on Stability of Vortex Flow over Slender Delta Wing with Dorsal Fin

Effects of Anhedral and Dihedral on a 75-deg Sweep Delta Wing

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