Dielectric Barrier Discharge Flow Control at Very Low Flight Reynolds Numbers

Greenblatt, David; Göksel, B.; Rechenberg, Ingo; Schüle, Chan Yong; Romann, Daniel; Paschereit, Christian Oliver

doi:10.2514/1.33388

Cited by 116 publications

(43 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For their inclined flat plate, they employed a wavelet algorithm to detect large-scale vortices in time-resolved particle image velocimetry (PIV) data, which revealed an interesting coalescence of smaller vortices produced near the actuator into one large coherent vortex advecting down the plate per cycle of actuation, in the case of f + = 1 (St = 0.23), and into two coherent vortices per cycle of actuation when f + = 0.5, both of which imply vortex shedding at St = 0.23. A similar configuration (with a dielectric-barrier discharge actuator) was studied by Greenblatt et al [27] (flat plate) and Benard et al [28] (NACA0015). For the flat plate at a = 20 • , 0.3 < f + < 0.6 provided the best lift enhancement, whereas f + > 3 was ineffective, and smoke visualization at f + = 0.4 showed a strong vortex advecting downstream along the chord; f + = 1.5 was optimal for a NACA0015 at a = 16 • .…”

Section: (B) Actuated Flowsmentioning

confidence: 89%

“…Recent studies have also documented the effect of the waveform on performance. It appears that periodic but pulsatile actuation or modulated highfrequency sinusoidal oscillation can produce performance equal to or greater than sinusoidal actuation at the same frequency [26,27,[29][30][31]. Indeed, it appears that pulses with as low a duty cycle as 5 per cent can be effective [27].…”

Section: (B) Actuated Flowsmentioning

confidence: 99%

See 1 more Smart Citation

Control of vortex shedding on two- and three-dimensional aerofoils

Colonius

Williams

2011

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

We review and expand on the control of separated flows over flat plates and aerofoils at low Reynolds numbers associated with micro air vehicles. Experimental observations of the steady-state and transient lift response to actuation, and its dependence on the actuator, aerofoil geometry and flow conditions, are discussed and an attempt is made to unify them in terms of their excitation of periodic and transient vortex shedding. We also examine strategies for closed-loop flow and flight control using actuation of leading-edge vortices.

show abstract

Section: (B) Actuated Flowsmentioning

confidence: 89%

Section: (B) Actuated Flowsmentioning

confidence: 99%

Control of vortex shedding on two- and three-dimensional aerofoils

Colonius

Williams

2011

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

show abstract

“…The objectives for separation control have covered various types of fluid and transport machinery. For the twodimensional airfoil flows, NACA airfoils [5][6][7][8][9][10], a flat-plate airfoil [11,12], and a low-Reynolds-number airfoil [13,14] have been investigated. Moreover, a linear cascade of turbine blades [15][16][17], a vertical-axis wind turbine [18], and cylinder and bluff-body flows [19][20][21][22] have also been the target of flow separation control.…”

mentioning

confidence: 99%

Multifactorial Effects of Operating Conditions of Dielectric-Barrier-Discharge Plasma Actuator on Laminar-Separated-Flow Control

et al. 2015

View full text Add to dashboard Cite

A substantial number of large-eddy simulations are conducted on separated flow controlled by a dielectric barrier discharge plasma actuator at a Reynolds number of 63,000. In the present paper, the separated flow over a NACA 0015 airfoil at an angle of attack of 12 deg, which is just poststall, is used as the base flow for separation control. The effects of the location and operating conditions of the plasma actuator on the separation control are investigated by a parametric study. The control effect is evaluated based on the improvement of not only the lift coefficient but also the drag coefficient over an airfoil. The most effective location of the plasma actuator for both lift and drag improvement is precisely confirmed to be upstream of the natural separation point. Even a low burst ratio is found to be sufficient to obtain the same improvements as the cases with a high burst ratio. The effective nondimensional burst frequency F is observed at 4 ≤ F ≤ 6 for the improvement in the lift coefficient and at 6 ≤ F ≤ 20 for that in the drag coefficient.The lift/drag ratio shows a clear peak at 6 ≤ F ≤ 10. To clarify the mechanism of the laminar-separation control, the effect of a turbulent transition is investigated. There is a clear relationship between the separation control effect and the turbulent transition at the shear layer. An earlier and smoother transition case shows greater improvements in the lift and drag coefficients. Flow analyses show that the cases with early and smooth turbulent transition can attach the separated flow further upstream, resulting in a higher suction peak of the pressure coefficient. In addition, another mechanism of the separation control is observed in which the lift coefficient is improved, not by the reattachment through the turbulent transition but by the large-scale vortex shedding induced by the actuation. It is possible to separate these two dominant mechanisms based on the effect of the turbulent transition on the separation control. Nomenclature a = speed of sound BR = burst ratio C D = drag coefficientlength scale D c = ratio between electrostatic body force added by plasma actuator and dynamic pressure D c;effe = effective D c value E i = electric field vector induced by plasma actuator e = total energy per unit volume F base = nondimensional base frequency for sine wave of input voltage; f base c∕u ∞ F = nondimensional frequency of burst wave; f c∕u ∞ f = frequency f base = base frequency for sine wave of input voltage f = frequency of burst wave M ∞ = freestream Mach number Pr = Prandtl number p = pressure Q c = electric charge q i = heat flux vector Re = Reynolds number St = Strouhal number S Suzen = body force vector determined from Suzen model S i = body force vector; Q c E i T = burst wave period T base = period of sine wave T off = period when sine wave switch is off during burst wave period T on = period when sine wave switch is on during burst wave period t = time u = velocity in chord direction . Member AIAA. Article in Advance / 1 AIAA JOURNAL Downloaded by U...

show abstract

“…[36][37][38][39][40][41] The actuator consists of two horizontally displaced electrodes separated by a dielectric material. The powered electrode is typically exposed to the surrounding gas, and the grounded electrode embedded beneath the dielectric.…”

Section: Micro-second Pulsed Dbd Plasma Actuatorsmentioning

confidence: 99%