Passive Control of Compressible Dynamic Stall

Martin, Preston B.; Wilson, Jacob; Directorate, Aeroflightdynamics; Berry, John D.; Wong, Tin-Chee; Moulton, Marty; Arsenal, Redstone; McVeigh, Michael A.

doi:10.2514/6.2008-7506

Cited by 31 publications

(19 citation statements)

References 10 publications

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“…Their major detractor is a significant drag penalty incurred in portions of the flight envelope where they are not needed. For example, Martin et al [3] showed that the combination of a transonic leading-edge glove (which lowered the local Mach number) and passive vortex generators was extremely effective at suppressing dynamic stall on a pitching airfoil. However, the effectiveness of the transonic glove and passive vortex generator combination diminished at higher Mach numbers above M ∞ 0.3-0.4 as a result of shocks generated by the passive vortex generator.…”

Section: Nomenclaturementioning

confidence: 98%

Mechanism of Vorticity Generation in Plasma Streamwise Vortex Generators

Wicks¹,

Thomas²,

Corke³

et al. 2015

AIAA Journal

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An experimental investigation into the mechanism of streamwise vorticity generation in an array of plasma streamwise vortex generators is presented. The array is flush mounted to a flat plate on which a nominally zero pressure gradient turbulent boundary layer develops upstream. The investigation is focused on characterization of the influence of freestream velocity, applied peak-to-peak voltage, length of the active electrode, and spanwise interelectrode spacing on streamwise vorticity generation. It is shown that the actuator creates wall-normal vorticity and reorients it into the streamwise direction. In addition, spanwise boundary-layer vorticity is reoriented into the streamwise direction. Scaling relations based on the vorticity transport equation are obtained and experimentally validated. These provide guidance for optimizing the actuators for particular flow control applications. NomenclatureA v = vortex cross-sectional area in the y-z plane E = electric field E pp = peak-to-peak excitation voltage F B = body force vector L = active surface electrode length M ∞ = freestream Mach number Re x = Reynolds number S xj = mean strain rate s xj = fluctuating strain rate U = streamwise mean velocity component h Ui = spanwise cycle-average mean velocity U ∞ = freestream velocity u j = j component velocity fluctuation u τ = wall friction velocity V = wall-normal mean velocity component V p = plasma-induced wall-normal velocity W = spanwise mean velocity component W P = plasma-induced spanwise mean velocity x, y, z = streamwise, wall-normal, and spanwise spatial coordinates, respectively δ = 99% boundary-layer thickness δ = boundary-layer displacement thickness λ = spanwise interelectrode spacing Γx = circulation ω x = streamwise component mean vorticity ω 0 x = streamwise vorticity fluctuation

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Section: Nomenclaturementioning

confidence: 98%

Mechanism of Vorticity Generation in Plasma Streamwise Vortex Generators

Wicks¹,

Thomas²,

Corke³

et al. 2015

AIAA Journal

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show abstract

“…[3][4][5][6][7] and research institutions (Refs. [8][9][10][11][12], although it appears that only NASA's Dynamic Stall Testing and Research Facility (DSTAR) and DLR's Transonic Wind Tunnel Göttingen (DNW-TWG) have recently published results with dynamic stall conditions for compressible flow. Similarly to most researchers, the method of a finite wing is used, with the wing suspended between two impermeable walls, oscillated with a pitching motion, for which the best known early experiments for helicopter airfoils come from McCroskey et al (Ref.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Dynamic Stall Performance for the EDI-M109 and EDI-M112 Airfoils

Gardner¹,

Richter²,

Mai³

et al. 2013

j am helicopter soc

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An experimental investigation of the dynamic performance of two new rotor blade airfoils was undertaken in a transonic wind tunnel. The EDI-M109 and EDI-M112 airfoils were tested at 0.3 ≤ M ≤ 0.5 for pitching motions with amplitude 0.5 • ≤ α ± ≤ 8 • and frequencies 3.3 Hz ≤ f ≤ 45 Hz. The results show the dynamic stall performance of both new airfoils, and the effect of frequency, amplitude, and higher order pitching motion on these results is described. The pitching moment peak size was found to have an approximately linear correlation to the normalized mean angular velocity, and thus test cases with the same maximum angle of attack and oscillation frequency had similar dynamic stall qualities. The correlation between low aerodynamic damping for high-frequency, low-amplitude pitching motion, and poor dynamic stall performance is shown to be low. The pitching moment peak of the EDI-M112 airfoil is shown to be smaller for M = 0.3 and 0.4, and peak for the EDI-M109 airfoil is lower at M = 0.5. The dynamic performance of the airfoils is compared to the OA209.

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“…16), or counterrotating vortex generators (Ref. 14) use energy from the oncoming flow to affect the flow. Prince et al (Ref.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Air Jets to Control Shock-Induced Dynamic Stall

Gardner¹,

Richter²,

Mai³

et al. 2014

J Am Helicopter Soc

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This paper shows experimental results for dynamic stall control on a dynamically pitching OA209 airfoil at Mach 0.5, with Reynolds numbers 1.9 × 10 6 and 0.85 × 10 6 . The control was by supersonic constant blowing on the suction side of the airfoil. Dry compressed air was blown normal to the airfoil chord, from portholes at 10% chord, with diameter 1% chord. At both Reynolds numbers, the OA209 without blowing experienced shock-induced stall with a hysteresis in lift and pitching moment around the static values, rather than the overshoot in forces typically associated with a dynamic stall vortex. The forces and the stall control were primarily functions of the maximum angle of attack, with full control of stall possible for maximum angles of attack of 14 • and less. The higher Reynolds number required relatively more blowing (higher C q , C μ ) to control the dynamic stall. Drag was reduced for separated flow, but the energy required in compressed air to achieve this was more than the savings in drag, and no cases were found in which flow control resulted in a reduction in total power used. Increasing the jet spacing resulted in equivalent flow control with less air use. Jets spaced at 20% chord and mass flux ratio C q = 0.004 (momentum ratio C μ = 0.016) resulted in a reduction of the pitching moment peak by 60%. The flow control with air jets was uncritical regarding the aerodynamic damping.

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Passive Control of Compressible Dynamic Stall

Cited by 31 publications

References 10 publications

Mechanism of Vorticity Generation in Plasma Streamwise Vortex Generators

Mechanism of Vorticity Generation in Plasma Streamwise Vortex Generators

Experimental Investigation of Dynamic Stall Performance for the EDI-M109 and EDI-M112 Airfoils

Experimental Investigation of Air Jets to Control Shock-Induced Dynamic Stall

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