Oscillation of Vortex Breakdown Location and Blowing Control of Time-Averaged Location

Mitchell, Anthony; Didier, Barberis; Molton, Pascal; Délery, Jean

doi:10.2514/2.1059

Cited by 55 publications

(10 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Small aspect ratio jets have been used for adding momentum from a location near the apex in the symmetry plane and parallel to the leading-edge [34,35] (see Figure 16), for along-the-core blowing underneath the vortex axis [36,37], for spanwise blowing underneath the vortex axis [38], and outward blowing from the leading-edge [39].…”

Section: Small Aspect Ratio Jetsmentioning

confidence: 99%

“…Along-the-core blowing [36,37] accelerates the axial flow in the core, and modifies the pressure gradient favourably. Figure 17 shows the effectiveness of various blowing/suction methods from various studies published in the literature [30,31,36,37,[40][41][42][43][44][45][46][47]. Here the effectiveness is defined as (∆x bd /c)/C µ , where ∆x bd is the change in breakdown location (positive corresponding to delay), c is the chord length and C µ is the momentum coefficient.…”

Section: Small Aspect Ratio Jetsmentioning

confidence: 99%

See 1 more Smart Citation

Review of flow control mechanisms of leading-edge vortices

Gursul

Wang

Vardaki

2007

Progress in Aerospace Sciences

135

View full text Add to dashboard Cite

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.

show abstract

Section: Small Aspect Ratio Jetsmentioning

confidence: 99%

Section: Small Aspect Ratio Jetsmentioning

confidence: 99%

Review of flow control mechanisms of leading-edge vortices

Gursul

Wang

Vardaki

2007

Progress in Aerospace Sciences

135

View full text Add to dashboard Cite

show abstract

“…This stagnation point, called the breakdown location, is unsteady and typically oscillates about some mean position along the axis of the vortex core. 16,17 As angle of attack is increased, the mean vortex breakdown location moves upstream over the delta wing (from the trailing edge towards the apex).…”

Section: Aiaa 2003-1103mentioning

confidence: 99%

DES Grid Resolution Issues for Vortical Flows on a Delta Wing and an F-18C

Morton

Steenman

Cummings

et al. 2003

41st Aerospace Sciences Meeting and Exhibit

View full text Add to dashboard Cite

An assessment of unstructured grids for use in Detached-Eddy Simulations (DES) of vortical flowfields over two configurations, a 70 degree delta wing and an F-18C are presented. The role of the grid in detached eddy simulations of vortical flowfields, including complex features such as vortex breakdown, is assessed on a delta wing with comparison to wind tunnel data. Adaptive mesh refinement is applied to the delta wing grid to improve the focus region aft of the vortex breakdown where massively separated flow exists and unsteady pressures are generated that could impact the loads on vertical tails of more complex configurations. The adaptively refined mesh is compared to the baseline mesh to determine the advantage of the adaptive mesh refinement approach for vortex breakdown. The focus region grid resolution is then applied to an F-18C in the region of the vortex generat ed from the leading edge extension (LEX). The resulting unsteady tail loads are compared to flight test data from the NASA F-18 HARV database. This paper represents one of the first times adaptive mesh refinement will be applied to a detached eddy simulati on of a flight vehicle configuration.

show abstract

“…Rusak and Lamb (1999) computed the location of breakdown predicted on a delta wing by their theory using experimentally measured velocity profiles, and FLOW 132 found it to match very well with observed locations. Experimental observations of vortex breakdown location by other researchers revealed an oscillatory behaviour about a mean position with a maximum magnitude of about 0.25 C (Payne et al (1986(Payne et al ( , 1988) & Mitchell et al (2000)).…”

Section: Delta Wing Vortex Breakdownmentioning

confidence: 79%

Stationary cavitation bubbles forming on a delta wing vortex

2014

View full text Add to dashboard Cite

collaborated with me at various stages of my dissertation. I would like to thank them all for their support and contribution towards this thesis. I would like to thank Kent Pruss for his time. There have been numerous occasions when Kent made sure I had what I needed to work over the weekend. I would also like to thank Bill Kirkpatrick, Marv Casey for their assistance in the machine shop. Dave Parsons deserves a special mention for all the expertise he provided during my time at MHL. I would also like to thank Melissa McGeorge and Sallie Kne for their time.

show abstract

Oscillation of Vortex Breakdown Location and Blowing Control of Time-Averaged Location

Cited by 55 publications

References 27 publications

Review of flow control mechanisms of leading-edge vortices

Review of flow control mechanisms of leading-edge vortices

DES Grid Resolution Issues for Vortical Flows on a Delta Wing and an F-18C

Stationary cavitation bubbles forming on a delta wing vortex

Contact Info

Product

Resources

About