Active Flow Control on a Nonslender Delta Wing

Williams, Nathan; Wang, Zhijin; Gursul, Ismet

doi:10.2514/6.2008-740

Cited by 9 publications

(4 citation statements)

References 12 publications

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“…The static aerodynamic forces and moments can be measured indirectly by integrating the surface pressure distribution [204] or directly by strain gauge balance, internal spring balance and load cell. The unsteady aerodynamic forces and moments acting on a maneuvering air vehicle [205] can be measured by using strain gauge balance and load cell.…”

Section: Flow Related Physical Verification and Validationmentioning

confidence: 99%

Design verification and validation in product lifecycle

2010

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Section: Flow Related Physical Verification and Validationmentioning

confidence: 99%

Design verification and validation in product lifecycle

2010

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“…In fact, for pre-stall incidences when vortex breakdown exists over the wing, the effect of the excitation on the normal force is negligible as shown in Figure 22. Figure 23 compares the effectiveness ∆C N /C µ for the unsteady blowing [51,52] and steady blowing [28,34,35]. It is seen that there is great potential in active flow control based on unsteady excitation in the post-stall lift enhancement.…”

Section: High-frequency Excitationmentioning

confidence: 99%

“…For nonslender delta wings, there is even greater potential with unsteady excitation [52], since the flow reattachment is likely to occur on the wing surface (see Figures 2 and 3).…”

Section: High-frequency Excitationmentioning

confidence: 99%

Review of flow control mechanisms of leading-edge vortices

Gursul

Wang

Vardaki

2007

Progress in Aerospace Sciences

135

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Vortex control concepts employed for slender and nonslender delta wings were reviewed. Important aspects of flow control include flow separation, vortex formation, flow reattachment, vortex breakdown, and vortex instabilities. The occurrence and relative importance of these phenomena strongly depend on the wing sweep angle. Various flow control methods were discussed: multiple vortices, control surfaces, blowing and suction, low-frequency and high-frequency excitation, feedback control, passive control with wing flexibility, and plasma actuators. For slender delta wings, control of vortex breakdown is achieved by modifications to swirl level and external pressure gradient acting on the vortex core. Effects of flow control methods on these two parameters were discussed, and their effectiveness was compared whenever possible. With the high-frequency excitation of the separated shear layer, reattachment and lift enhancement in the post-stall region is observed, which is orders of magnitude more effective than steady blowing. This effect is more pronounced for nonslender wings. Re-formation of vortices is possible with sufficient amplitude of forcing at the optimum frequency. Passive lift enhancement on flexible wings is due to the self-excited wing vibrations, which occur when the frequency of wing vibrations is close to the frequency of the shear layer instabilities, and promote flow reattachment.

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“…The actuation at reduced frequencies F + ≈ 1-2 lead to a significant increase in lift in the post-stall regime (α > α max ) by the generation of a vortex, if the shear layer emanating from the leading edge is exposed to pulsed blowing. Silimar results were gained by Williams et al [15].…”

mentioning

confidence: 74%

Dynamic Actuation for Delta Wing Post Stall Flow Control

Kölzsch

Blanchard

Breitsamter

2016

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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The manipulation of delta wing flow by active and passive flow control methods is of great interest for increasing the performance (e.g. lift enhancement) of such configurations. This work presents experimental results in the post-stall regime at very high angles of attack (α = 35-45• ) on a 65• sweptback generic half delta wing configuration (VFE-2 geometry) with sharp leading edge using slot actuators for pulsed blowing along the leading edge. The study comprises results of force, velocity and pressure measurements and substantiates the receptivity of the shear layer for the pulsed excitation. For α = 35• , an actuation at F + ≈ 2.7 effects a retardation of vortex breakdown. For α = 45• , the optimum pulse frequency was found at F + = 1.0-1.5, which leads to the re-establishment of a burst vortex and a significant increase in lift, thus satisfying the aim of enhancing aerodynamic performance.

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Active Flow Control on a Nonslender Delta Wing

Cited by 9 publications

References 12 publications

Design verification and validation in product lifecycle

Design verification and validation in product lifecycle

Review of flow control mechanisms of leading-edge vortices

Dynamic Actuation for Delta Wing Post Stall Flow Control

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