Characteristics of drag-reduced turbulent boundary layers with pulsed-direct-current plasma actuation

Duong, Alan; Corke, Thomas; Thomas, Flint O.

doi:10.1017/jfm.2021.167

Cited by 26 publications

(12 citation statements)

References 27 publications

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“…Thus, besides supporting the primary conclusion of the present study, the increase in 3u 2 i u o with increasing Re τ also suggests that the efficacy of the OSA strategy will likely improve further at higher Reynolds numbers. These arguments encourage future work on multiple fronts, including: (i) investigation of the flow physics associated with enhanced inner-outer coupling at high Re τ , and (ii) testing the efficacy of practicably deployable spanwise flow oscillation schemes, such as through plasma actuators (Hehner, Gatti & Kriegseis 2019;Thomas et al 2019;Duong, Corke & Thomas 2021), passive wavy walls (Ghebali, Chernyshenko & Leschziner 2017), etc. towards achieving energy-efficient DR via the OSA pathway.…”

Section: Discussionmentioning

confidence: 99%

On the relationship between manipulated inter-scale phase and energy-efficient turbulent drag reduction

Deshpande,

Chandran,

Smits

et al. 2023

J. Fluid Mech.

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We investigate the role of inter-scale interactions in the high-Reynolds-number skin-friction drag reduction strategy reported by Marusic et al. (Nat. Commun., vol. 12, 2021). The strategy involves imposing relatively low-frequency streamwise travelling waves of spanwise velocity at the wall to actuate the drag generating outer scales. This approach has proven to be more energy efficient than the conventional method of directly targeting the drag producing inner scales, which typically requires actuation at higher frequencies. Notably, it is observed that actuating the outer scales at low frequencies leads to a substantial attenuation of the major drag producing inner scales, suggesting that the actuations affect the nonlinear inner–outer coupling inherently existing in wall-bounded flows. In the present study, we find that increased drag reduction, through imposition of spanwise wall oscillations, is always associated with an increased coupling between the inner and outer scales. This enhanced coupling emerges through manipulation of the phase relationships between these triadically linked scales, with the actuation forcing the entire range of energy-containing scales, from the inner (viscous) to the outer (inertial) scales, to be more in phase. We also find that a similar enhancement of this nonlinear coupling, via manipulation of the inter-scale phase relationships, occurs with increasing Reynolds number for canonical turbulent boundary layers. This indicates improved efficacy of the energy-efficient drag reduction strategy at very high Reynolds numbers, where the energised outer scales are known to more strongly superimpose and modulate the inner scales. Leveraging the inter-scale interactions, therefore, offers a plausible mechanism for achieving energy-efficient drag reduction at high Reynolds numbers.

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Section: Discussionmentioning

confidence: 99%

On the relationship between manipulated inter-scale phase and energy-efficient turbulent drag reduction

Deshpande,

Chandran,

Smits

et al. 2023

J. Fluid Mech.

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“…Because the fast gas heating is difficult to measure directly in experiments, these pressure waves, usually observed on a microsecond timescale, are commonly used as the indicator of the fast gas heating. The pulsed-DC waveform is different from the waveforms both in ac-DBD and ns-DBD [14,15]. So, both the characteristics of pulsed-DC DBD on a microsecond timescale (corresponding to the pressure wave) and millisecond timescale (corresponding to the wall-bounded jet) are investigated in the current research in an attempt to clarify the basic properties of pulsed-DC DBD.…”

Section: Flow Characteristics Of Pulsed-dc Dbd On a Microsecond Times...mentioning

confidence: 98%

“…the traveling/oscillating body force near the wall [9,10]. This motivated many researchers to pursue similar ideas, including the dielectric barrier discharge (DBD) plasma actuator, to produce similar traveling/oscillating body force in the near-wall region and get skin friction drag reduction [11][12][13][14][15][16]. DBD actuators are commonly used in boundary layer separation control and have the advantage of a simple structure and small power consumption [17], making them an ideal device for achieving net power saving in turbulent drag reduction.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, in 2019, a new high-voltage waveform named pulsed-DC high voltage was used to in DBD(pulsed-DC DBD) and was applied in turbulent drag reduction by Duong and Thomas et al [14,15]. The pulsed-DC waveform consists of a high-voltage DC combined with a negative pulse, which is more like the high-voltage pulses in ns-DBD rather than the sinusoidal high voltage in ac-DBD.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of a dielectric barrier discharge plasma actuator driven by pulsed-DC high voltage

Su¹,

Zong²,

Liang³

et al. 2021

J. Phys. D: Appl. Phys.

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Dielectric barrier discharge using pulsed-DC high voltage (pulsed-DC DBD) have been proven to be capable of effectively reducing skin friction drag in turbulent boundary layers with limited power consumption, thus producing significant net power savings. In this work, the characteristics of pulsed-DC DBD, including power consumption, induced flow structure, thermal effect, and body force, are investigated sequentially. Both the power consumption and pressure waves produced by pulsed-DC DBD are similar to that of DBD using nanosecond pulses (ns-DBD), whereas the wall-bounded jet structure resembles that of DBD using sinusoidal high voltage (ac-DBD). A curved wall jet is induced at a small pulse width, which turns into a straight one due to the combined effect of momentum and thermal addition when the pulse width increases. With increasing pulse width, the induced body force goes up while the thermal effect weakens. Although pulse frequency has no impact on the wall-bounded jet topology, the body force increases with pulse frequency because of the enhanced energy entrainment. With these results, four parameters that affect the performance of pulsed-DC DBD are extracted, including the pulse leading edge, pulse width, frequency, and amplitude, which lays the foundation for the optimization of pulsed-DC DBD.

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“…Active drag reduction mainly uses additional equipment to transport substances or energy to the surface of the vehicle and its turbulent boundary layer for drag reduction by controlling the flow field structure, for example, drag reduction by polymer addition, [4][5][6][7][8][9][10][11][12] boundary layer heating, [13] wall suction/ejection, [14][15][16][17][18] and wall vibration. [19,20] The method of reducing drag without energy input is called "passive" drag reduction. Passive drag reduction technology achieves drag reduction by changing or optimizing the surface structures of the object to change the flow field structure.…”

Section: Introductionmentioning

confidence: 99%

Focus on Bioinspired Textured Surfaces toward Fluid Drag Reduction: Recent Progresses and Challenges

et al. 2021

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After a long period of biological evolution, natural creatures will inevitably evolve body surfaces suitable for the living environment. The functions of natural biological surfaces are abundant and powerful, including antiadhesion, self‐cleaning, drag reduction, anti‐icing, wear resistance, and other characteristics. In the context of coping with the energy crisis, inspired by natural biological surface microstructures, researchers explore biomimetic surface microstructures that reduce fluid drag and investigate the mechanisms of drag reduction. Herein, mainly the current state of research on biomimetic textured surfaces that can be applied to fluid drag reduction is reviewed and the microstructures’ morphology, drag reduction mechanisms, and the fabrication techniques of textured surfaces are discussed in detail. In particular, the experimental methods for measuring the drag reduction effect of textured surfaces are introduced, which is extremely rare. The article concludes with a summary of existing problems and future directions in the research of biomimetic surface drag reduction technology. This Review can provide a reference for practical application and laboratory research of drag reduction in marine transportation, military weapons, aviation, and pipeline systems.

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Characteristics of drag-reduced turbulent boundary layers with pulsed-direct-current plasma actuation

Abstract: Abstract

Cited by 26 publications

References 27 publications

On the relationship between manipulated inter-scale phase and energy-efficient turbulent drag reduction

On the relationship between manipulated inter-scale phase and energy-efficient turbulent drag reduction

Characteristics of a dielectric barrier discharge plasma actuator driven by pulsed-DC high voltage

Focus on Bioinspired Textured Surfaces toward Fluid Drag Reduction: Recent Progresses and Challenges

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