Airfoil Flow Experiment on the Duty Cycle of DBD Plasma Actuator

Asada, Keiichi; Ninomiya, Yoshihiko; Oyama, Akira; Fujii, Kozo

doi:10.2514/6.2009-531

Cited by 51 publications

(46 citation statements)

References 4 publications

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“…Figure 6 shows the mean pressure coefficients for the simulation and experimental results. The detailed experimental setup and measuring method are given in previous papers [58,59]. It is noted that, since the plasma actuator is located at x∕c 0.05, the pressure data at this location cannot be measured in this experiment.…”

Section: F Flow Condition and Computational Casementioning

confidence: 98%

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

et al. 2015

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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...

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Section: F Flow Condition and Computational Casementioning

confidence: 98%

“…The flow condition is supposed to be the same as our previous experiment at a low Reynolds number [58]. In this experiment, the freestream velocity was 10 m∕s, and the chord length of the NACA 0015 airfoil was 10 cm, resulting in a Reynolds number of 63,000.…”

Section: F Flow Condition and Computational Casementioning

confidence: 99%

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

et al. 2015

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“…Many researchers investigate the optimum F + value for separation control over an airfoil, and there are two assertions: 1) F + ≈ O(1) is the optimum frequency 11, 12, 14 and 2) F + ≈ O(10) is the optimum frequency. 13,15 This inconsistency may be due to lack of understanding of the separation control mechanism.…”

Section: Introductionmentioning

confidence: 94%

“…Flow conditions is set same as the previous experimental study 15 to conduct the validation. Free stream Mach number is M ∞ = 0.2.…”

Section: Computational Flow Conditionsmentioning

confidence: 99%

Burst Frequency Effect of DBD Plasma Actuator on the Control of Separated Flow over an Airfoil

Asada

Fujii

2012

6th AIAA Flow Control Conference

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The flow fields around NACA0015 airfoil, separation over which is controlled by a DBD plasma actuator are simulated by implicit large eddy simulation with compact difference scheme, and the burst frequency effect of DBD plasma actuator on the control of separated flow over the airfoil is discussed. The Reynolds number based on chord length is set to 63,000 and the angle of attack is set to 14 [deg]. The DBD plasma actuator is installed at the 0 % and 5 % chord length from the leading edge, and actuated in burst mode. For the burst mode, the nondimensional burst frequency is set to 1 and 6. Through the present analysis, the two mechanisms of separation control are discussed. The first mechanism enhance the vortex shedding from the separation shear layer and avoid the massive separation from the leading edge on burst mode with nondimensional burst frequency of 1. The second mechanism improves the airfoil performance by suppressing the separation region on the burst mode with nondimensional burst frequency of 6. In addition, it is clarified that the first mechanism is more sensitive to the location of the DBD plasma actuator than the second mechanism and it is associated with large fluctuation of lift.

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“…In these studies, continuous DC current was applied with different parameters such as DC voltage, frequencies and shape of the frequency waves. Some studies demonstrated that the so-called 'burst mode' (schematically shown in figure 2) with duty cycles has better capability to control flow separation with less energy consumption [4,6,7,10,14,16,18]. Here, the burst mode actuation indicates that the base high-frequency wave signals are periodically switched on and off with a low burst frequency.…”

Section: Introductionmentioning

confidence: 99%

High-performance computing-based exploration of flow control with micro devices

Fujii

2014

Phil. Trans. R. Soc. A.

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One contribution of 13 to a Theme Issue 'Aerodynamics, computers and the environment' . Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai, Chuo-ku, Sagamihara 252-5210, JapanThe dielectric barrier discharge (DBD) plasma actuator that controls flow separation is one of the promising technologies to realize energy savings and noise reduction of fluid dynamic systems. However, the mechanism for controlling flow separation is not clearly defined, and this lack of knowledge prevents practical use of this technology. Therefore, large-scale computations for the study of the DBD plasma actuator have been conducted using the Japanese Petaflops supercomputer 'K' for three different Reynolds numbers. Numbers of new findings on the control of flow separation by the DBD plasma actuator have been obtained from the simulations, and some of them are presented in this study. Knowledge of suitable device parameters is also obtained. The DBD plasma actuator is clearly shown to be very effective for controlling flow separation at a Reynolds number of around 10 5 , and several times larger lift-to-drag ratio can be achieved at higher angles of attack after stall. For higher Reynolds numbers, separated flow is partially controlled. Flow analysis shows key features towards better control. DBD plasma actuators are a promising technology, which could reduce fuel consumption and contribute to a green environment by achieving high aerodynamic performance. The knowledge described above can be obtained only with high-end computers such as the supercomputer 'K'.

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Airfoil Flow Experiment on the Duty Cycle of DBD Plasma Actuator

Cited by 51 publications

References 4 publications

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

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

Burst Frequency Effect of DBD Plasma Actuator on the Control of Separated Flow over an Airfoil

High-performance computing-based exploration of flow control with micro devices

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