Effect of Passive Bleeding on Flow Structure over a Nonslender Delta Wing

Çelik, Alper; Çetin, Cenk; Yavuz, Mehmet Metin

doi:10.2514/1.j055776

Cited by 6 publications

(2 citation statements)

References 41 publications

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“…Passive bleed exploiting the natural pressure difference between the upper and lower surfaces can be an effective method to manipulate the tip/edge vortices. Bleed slots were placed near the wing tip/edge for rectangular wings [32], delta wings [33], and double-delta wings [34].…”

Section: Bleedmentioning

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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Section: Bleedmentioning

confidence: 99%

Flow Control of Tip/Edge Vortices

Gursul

Wang

2018

AIAA Journal

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“…Passive bleeding along the leading edge was introduced as an effective method to delay vortex breakdown by Çelik et al[49], and they reported the configuration of the bleeding holes as an important parameter in vortex breakdown control.Geometrical characteristics of delta wings, including sweep angle, wing flexibility, leading edge geometry, and thickness-to-chord ratio / ,have significant influence on flow structure and aerodynamic performance. Sweep angle effect was extensively studied since 1964[13], and Gursul and Batta[50] employed variable sweep angle delta wing to particularly control the location of vortex breakdown.…”

mentioning

confidence: 99%

Effect of thickness-to-chord ratio on aerodynamics of non-slender delta wing

Ghazijahani

Yavuz

2019

Aerospace Science and Technology

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, 84 pages Flow characterization over delta wings have gained attention in recent decades due to their prevailing usage in designs of unmanned air vehicles (UAVs). In literature, only a few studies have reported wing thickness effect on both the aerodynamic performance and detailed flow structure over delta wings. In the present investigation, the effect of thickness-to-chord (/) ratio on aerodynamics of a non-slender delta wing with 45 degree sweep angle is characterized in a low-speed wind tunnel using laser illuminated smoke visualization, surface pressure measurements, particle image velocimetry, and force measurements. The delta wings with / ratios varying from 2 % to 15 % are tested at broad ranges of angle of attack and Reynolds number. The results indicate that the effect of / ratio on flow structure is quite substantial. Considering the low angles of attack where the wings experience leading edge vortex structure, the strength of the vortex structure increases as the / ratio increases. However, low / ratio wings have pronounced surface separations at higher angle of attack compared to the high / ratio wings. These results are well supported by the force measurements such that high / ratio wings induce higher lift coefficients, CL, at vi low angles of attack, whereas maximum CL values are higher and appear at higher angle of attack for low / ratio wings. This indicates that low / ratio wings are more resistive to the stall condition. Considering the lift-to-drag ratio, CL/CD, increase in / ratio induces remarkable drop in CL/CD values.

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