Stall cell formation over a post-stall airfoil: effects of active perturbations using plasma actuators

Esfahani, Ata; Webb, Nathan J.; Samimy, Mo

doi:10.1007/s00348-018-2588-y

Cited by 10 publications

(3 citation statements)

References 48 publications

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“…However, as was discussed earlier, the momentum generated by these actuators is relatively small, and thus their application is limited to flows with speeds less than about 50 m s −1 . Over the past 15 years, NS-DBD actuators, which generate thermal perturbations rather than momentum (as shown in figure 3), have been used for flow separation control over airfoils [17,39,41,45]. However, there has been a general lack of understanding on the actual control mechanism of NS-DBD actuators.…”

Section: Sample Afc Results In Separated Flows Using Ns-dbd Plasma Ac...mentioning

confidence: 99%

“…In terms of application for flow control, the primary difference between LAFPAs and NS-DBD actuators is that while LAFPAs produce spatially-localized, discrete perturbations (and are typically used in groups of actuators distributed throughout the receptivity region, as shown in figure 1), the NS-DBD actuators produce spatially distributed perturbations near the edge of the exposed electrode nearest the covered electrode. Recently, NS-DBD actuators have been used to control the flow over airfoils in both static stall (flow separation over a stationary airfoil) and dynamic stall (flow separation over an oscillating airfoil) conditions by manipulating the instabilities associated with the flow [17,[39][40][41]. Little [15] provided more details on the nature and operation of NS-DBD actuators.…”

Section: Ns-dbd Plasma Actuatorsmentioning

confidence: 99%

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Reinventing the wheel: excitation of flow instabilities for active flow control using plasma actuators

Samimy¹,

Webb²,

Esfahani³

2019

J. Phys. D: Appl. Phys.

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Flow control is typically used to manipulate a flow's natural behavior to alter its effects on a vehicle or system. When active flow control (AFC) is used in aerospace applications, the actuation can be turned on/off or adapted to changing flight conditions. AFC techniques in which significant gains can be achieved with relatively small cost are most beneficial and are the subject of this paper. Flows with the Kelvin-Helmholtz (K-H) instability, which are present in many aerospace applications, are amenable to AFC and have been the subject of research for over five decades. The K-H instability can amplify any natural or artificiallyseeded thermal, acoustic, or hydrodynamic perturbations over a wide range of frequencies. These perturbations can grow and eventually roll up into large-scale flow structures, which, in turn, can dominate important processes such as entrainment, mixing, momentum and heat trasport, and aeroacoustic noise. However, the application of active flow control was limited to low-speed flows in the earlier decades of study due to the shortcomings of the available actuators. The recent development of plasma actuators, capable of producing simultaneously high-amplitude and high-bandwidth thermal perturbations, has extended the AFC applications to high-speed and high-Reynolds number flows of interest in aerospace, hence the title: reinventing the wheel. In this paper, two classes of such plasma actuators, namely localized arc filament plasma actuators and nanosecond dielectric-barrier discharge plasma actuators, are briefly discussed and their applications in two very different flows are presented to highlight the advances made in the community in the use of plasma actuators for aerospace applications. In addition, there is a discussion of further advances that must be made in the development of these actuators to move the techniques from laboratory to in-flight use.

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Section: Sample Afc Results In Separated Flows Using Ns-dbd Plasma Ac...mentioning

confidence: 99%

Section: Ns-dbd Plasma Actuatorsmentioning

confidence: 99%

Reinventing the wheel: excitation of flow instabilities for active flow control using plasma actuators

Samimy¹,

Webb²,

Esfahani³

2019

J. Phys. D: Appl. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…There are various active fluid control techniques including suction and blowing [17][18][19][20], synthetic jets [21][22][23]. Recently, the research on the flow control by plasma actuators has been performed [24][25][26][27][28][29][30][31]. The plasma actuator is a structure composed of upper and lower electrodes and a dielectric layer, as shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

2019

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During insect flight, a feathering motion of the wing’s controls vortex shedding for lift enhancement. In this study, in order to control the flow around a wing flapping with simplified sinusoidal motion, plasma actuators were introduced to simplify the complex feathering motion. In a wind tunnel, a smoke-wire method was enacted to visualize the flow fields around an oscillating plate with an attack angle of 4° in a uniform flow for the baseline and controlled cases. The actuator placed around the leading edge was found to suppress the flow separation on the top surface. Numerical simulations were performed to investigate the control effects on the fluctuating lift, where the control effects by the intermittently driven actuator were also predicted. The actuator installed on the top surface throughout the up-stroke motion was found to suppress vortex shedding from the trailing edge, which resulted in an 11% lift enhancement compared to the baseline case. In regard to the effects of the installation position, it was found that the actuator placed on the top surface was effective, compared to the cases for installation on the bottom surface or both surfaces.

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An experimental investigation of deep dynamic stall control using plasma actuators

et al. 2022

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Stall cell formation over a post-stall airfoil: effects of active perturbations using plasma actuators

Cited by 10 publications

References 48 publications

Reinventing the wheel: excitation of flow instabilities for active flow control using plasma actuators

Reinventing the wheel: excitation of flow instabilities for active flow control using plasma actuators

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

An experimental investigation of deep dynamic stall control using plasma actuators

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