Wing tip vortex control using synthetic jets

Margaris, P; Gursul, Ismet

doi:10.1017/s0001924000001536

Cited by 31 publications

(13 citation statements)

References 19 publications

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“…Intuitive control approaches of a tip vortex lead control engineers to actuate in the tip region of the control surface. Examples of this type of control use momentum injection through different configuration slots in the wing tip region (Margaris & Gursul 2006, 2010Edstrand & Cattafesta 2015). Alternative control strategies have modified the lift distribution through rapidly actuated miniature Gurney flaps along the trailing edge (Matalanis & Eaton 2007) and through trailing-edge blowing (Taira & Colonius 2009).…”

Section: Introductionmentioning

confidence: 99%

Active attenuation of a trailing vortex inspired by a parabolized stability analysis

Edstrand¹,

Sun²,

Schmid³

et al. 2018

J. Fluid Mech.

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Designing effective control for complex three-dimensional flow fields proves to be nontrivial. Oftentimes, intuitive control strategies lead to suboptimal control. To navigate the control space, we utilize a linear parabolized stability analysis to guide the design of a control scheme for a trailing vortex flow field aft of a NACA0012 half-wing at an angle of attack α = 5 • and a chord-based Reynolds number Re = 1000. The stability results show that the unstable mode with the smallest growth rate (fifth wake mode) provides a pathway to excite a vortex instability, whereas the principal unstable mode remains in the wake of the wing. Inspired by this finding, we perform direct numerical simulations that excite each mode with body forces matching the shape function from the stability analysis. Relative to the baseline uncontrolled case, the principal wake mode reduces the vortex length, while the fifth wake mode further shortens the tip vortex. Analogously, the streamwise circulation of the trailing vortex is found to be significantly reduced. From these results, we conclude that a rudimentary linear stability analysis can provide key insight into the underlying physics and help engineers design more effective control.

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Section: Introductionmentioning

confidence: 99%

Active attenuation of a trailing vortex inspired by a parabolized stability analysis

Edstrand¹,

Sun²,

Schmid³

et al. 2018

J. Fluid Mech.

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“…This could be useful in some applications as will be discussed later on. Turbulence ingestion into the developing tip vortex can be achieved for much lower momentum coefficients (on the order of 0.1%) with synthetic jets [55].…”

Section: B Control Of Tip Vortices Of High Aspect Ratio Wingsmentioning

confidence: 99%

Flow Control of Tip/Edge Vortices

Gursul

Wang

2018

AIAA Journal

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Location, strength and structure of tip and edge vortices shed from wings and bodies can be manipulated by using flow control techniques. Flow physics of these approaches involve flow separation from the edge, roll-up into the vortex, wing flow regime, vortex instabilities, vortex-vortex interactions, and vortex-turbulence interactions. Actuators include continuous and unsteady blowing and suction, bleed, and control surfaces, which add momentum, vorticity and turbulence into the vortices. It is noted that actuation may have effects on more than one aspect of the flow phenomena. A comparative review of the control of delta wing vortices, tip vortices, and afterbody vortices is presented. The delay of vortex breakdown and the promotion of flow reattachment require different considerations for slender and nonslender delta wings, and may not be possible at all. Tip vortices can be controlled to increase the effective span, to generate rolling moment, to attenuate wing-rock, and to attenuate vortex-wing interactions. While there are different approaches for each application, opportunities for future research on turbulence ingestion, bleed, and excitation of vortex instabilities exist. Recent research also indicates that active and passive flow control can be used to manipulate the afterbody vortices in order to reduce the drag.

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“…These jet vortices have previously been generated through: a) blowing at an angle to the freestream direction; 11 b) self-generated jets (bleed) ejected perpendicular to the wing surface, where the pressure differential between the two wing surfaces provides the input energy; 12 and c) synthetic jets. 13 There is also evidence that far-wake interactions of co-rotating and counter-rotating vortex pairs can be affected by turbulence ingestion from blowing. [14][15][16] It has been theoretically shown that three-dimensional instabilities may grow in a counter-rotating vortex pair.…”

Section: Introductionmentioning

confidence: 99%

Control of Afterbody Vortices by Blowing

Jackson

Wang

Gursul

2015

45th AIAA Fluid Dynamics Conference

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An experimental study has been performed to examine the effect of blowing via a pair of jets from the upswept face of a slanted base cylinder, upon the development of the afterbody vortex flow field. Jet vortices initially interact with the shear layer separated from the upswept section. The nature of the early interactions between the jet and shear layer is highly dependent upon the blowing direction. For most blowing configurations tested, the shear layer becomes wrapped around the jet vortex. The most significant evidence of modification of the afterbody vortex pair was found when initiating a jet vortex further outboard and closer to the shear layer. The jet/vortex interactions initially cause the afterbody vortices to form further outboard, at a greater distance from the surface, and with a smaller vortex core. There is a reduction in the circulation over the first half of the afterbody length, before it recovers to baseline levels at the trailing edge. The vortex pair appears more diffuse near the trailing edge, but this is a result of increased meandering. Nomenclature am = meandering amplitude xj = streamwise jet location Aj = cross-sectional area of jet y = normal distance c = chord length of upswept face z = spanwise distance Cµ = jet momentum coefficient, ρAjUj 2 /0.5ρU∞ 2 S zj = spanwise jet location D = diameter of fuselage α = fuselage incidence angle L = length of afterbody αj = jet incidence angle r = distance from vortex center β = fuselage yaw angle Re = Reynolds number, ρU∞D/µ βj = jet yaw angle S = cross-sectional area of fuselage Γ = circulation Uj = jet velocity µ = viscosity U∞ = freestream velocity ρ = density V = crossflow velocity ω = vorticity x = streamwise distance

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Wing tip vortex control using synthetic jets

Cited by 31 publications

References 19 publications

Active attenuation of a trailing vortex inspired by a parabolized stability analysis

Active attenuation of a trailing vortex inspired by a parabolized stability analysis

Flow Control of Tip/Edge Vortices

Control of Afterbody Vortices by Blowing

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