Localized Arc Filament Plasma Actuators Research Articles

Active control of coupling and its effect on near-field pressure fluctuations in supersonic rectangular twin jets

Supersonic rectangular twin jets (SRTJ) are of interest for current and future generations of tactical aircraft. However, the adverse effects of screech-loop coupling have previously been documented to significantly increase the near-field (NF) pressure fluctuations. These high-amplitude pressure fluctuations have the potential to fatigue and damage nearby aft components of the aircraft. Previous studies have documented that the NF pressure fluctuation level depends on the coupling of the jets: in-phase coupling along the twin jets’ minor axes produces stronger NF pressure fluctuations than that of out-of-phase coupling. The objective of this work is to further investigate the effects of coupling modes on NF pressure fluctuations in SRTJ and to mitigate the adverse effects of coupling using active flow control. Localized arc filament plasma actuators are employed to alter the SRTJs’ coupling mode by leveraging natural flow instabilities with minimal power input. A NF microphone array is used for simultaneous coupling and NF pressure fluctuation measurements. Schlieren imaging and spectral proper orthogonal decomposition are used to assess the effects of control on the flow field. The effect of excitation at various frequencies and actuation patterns on coupling and NF pressure fluctuations in different flow regimes are explored and discussed.

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

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 artificially-seeded 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.

Excitation of Free Shear-Layer Instabilities for High-Speed Flow Control

Free shear layers are building blocks of many flows of interest in applications, including jets, cavity flows, and separated flows. It was found several decades ago that free shear layers are unstable to small perturbations over a wide range of frequencies, that they are dominated by coherent large-scale structures (even at high Reynolds numbers), and that the dynamics of these structures dominate important processes: entrainment, mixing, momentum transport, and noise generation. These findings motivated extensive research activities to actively control their development using excitation of instabilities, but early experimental research focused primarily on the control of low-speed, low-Reynolds-number free shear layers. This extensive body of the literature is briefly reviewed. The authors’ recent work using localized arc filament plasma actuators in jets shows that free shear layers respond to the excitation over a large range of conditions that have been explored: jet Mach number (up to 1.65), convective Mach number (up to 1), and Reynolds number (up to ). However, the nature of large-scale structures, shear-layer growth rate, and generation of Mach waves all depend on the jet Mach number and compressibility level. The results clearly demonstrate the similarity of instability processes and development of large-scale structures in free shear layers, regardless of the Mach or Reynolds numbers.

Near-field pressure waveform analysis of an excited Mach 0.9 jet

This work explores the effects of axisymmetric, helical, and flapping mode perturbations over a range of Strouhal numbers on the near-field pressure of an axisymmetric Mach 0.9 jet with a Reynolds number of 6.2 × 105. Excitation is generated by eight localized arc filament plasma actuators uniformly distributed around the nozzle exit. The excitation of jet shear layer instabilities resulted in large-scale structures. The signature of these structures in the irrotational near field appears as high-amplitude hydrodynamic pressure fluctuations with wavepacket-like growth, saturation, and decay. The excitation Strouhal number and, perhaps more importantly, the azimuthal mode, are seen to strongly affect the spatial evolution of the wavepacket in both axial and radial directions. The dominant excitation Strouhal number is around 0.3, and the most significant effect on the jet statistical properties (such as distributions of velocity and pressure) occurs further downstream for the flapping mode in comparison to the axisymmetric mode. Dynamic mode decomposition is performed to further describe the modal behavior and evolution of hydrodynamic pressure fluctuations. The pressure response in the near field of jet plumes in flapping mode excitation is shown to exhibit two azimuthal mode behaviors: axisymmetric and flapping. An empirical model of hydrodynamic pressure distribution is established with normalized axial and radial profiles. The amplitude and distribution of the hydrodynamic pressure component are well depicted by the empirical reconstruction.

Control of Supersonic Cavity Flow Using Plasma Actuators

Cavity flows are present in a wide range of aerospace applications. The pressure fluctuations associated with cavity resonance have made them the target of significant flow control efforts aimed at suppressing resonance. A potential scramjet application for cavity flows may require resonance enhancement in addition to resonance suppression. Localized arc filament plasma actuators have demonstrated the ability to control a high subsonic cavity flow. This work investigates the control authority of the localized arc filament plasma actuators in a supersonic () cavity flow. The localized arc filament plasma actuators significantly suppress the primary cavity resonance of a naturally and strongly resonating cavity. Additionally, the trend in effectiveness suggests that introducing mode competition through the excitation of the Kelvin–Helmholtz instability, and thereby influencing the shear-layer structure formation process, is the likely control mechanism. The effects of two-dimensional and three-dimensional excitation are explored. Although two-dimensional excitation achieves the greatest resonance suppression, three-dimensional excitation shows similar suppression with significantly less sensitivity to the excitation Strouhal number, making it more desirable for practical applications. In a weakly resonating cavity, the flow significantly responds to excitation near the resonance Strouhal numbers. However, electromagnetic interference makes it difficult to quantify the level of resonance enhancement.

Exploring Physics and Control of Twin Supersonic Circular Jets

The closely spaced twin-jet configuration often seen in military aircraft is distinct from the single jet in both the flowfield and acoustic field. The twin-jet plumes interact with each other weakly or strongly, depending upon the distance between the two jets, the jet operating flow regime, and the Mach number. In the current study, the interaction mechanisms and coupling of a supersonic twin jet exhausting from biconical converging–diverging nozzles with a design Mach number of 1.23 at a separation distance of two nozzle exit diameters are investigated using near-field pressure measurements and phase-locked flow visualization. Across a series of jet operating Mach numbers, the twin-jet plumes feature three major jet azimuthal modes: axisymmetric, helical, and flapping. The jet flapping mode is strongly augmented in the twin-jet configuration compared to the single-jet case. Along the twin-jet plane, which is also the plane of the jet flapping direction, jet plumes with coherent flow structures are observed to move up and down. Because of the nature of the jet flapping motion, the near-field pressure fluctuations are markedly amplified at low Strouhal numbers, particularly along the twin-jet plane for further downstream locations where the coherent structures are developed and large. Localized arc filament plasma actuators are implemented as an active flow control tool on both nozzles, just upstream of nozzle exit, to explore the coupling mechanisms. The results show that decoupling and coupling of twin-jet plumes can both be achieved, depending on the jet operating condition and the excitation parameters employed.

Large-Eddy Simulation of Plasma-Based Active Control on Imperfectly Expanded Jets

Jet flow control is important for mixing enhancement and noise mitigation. In previous efforts, we have used validated simulations to examine the effect of localized arc filament plasma actuators (LAFPA) on perfectly expanded Mach 1.3 jets. Here, we extend the analysis to an underexpanded jet at the same Mach number to examine the effect of shocks and expansions on control authority. After validation of the baseline flow, it is shown that the downstream evolution is relatively independent of Reynolds number. Simulations performed at different values of upstream pressure indicate that the higher stagnation pressure yields shock cells that are quantitatively stronger but qualitatively similar to those observed for the lower upstream stagnation pressure condition. For control simulations, axisymmetric mode pulsing is considered at two different Strouhal numbers of St = 0.3 and St = 0.9. These simulations show that the response of the jet to flow control is a strong function of the actuation frequency. Relative to the no-control case, actuating at the column-mode instability frequency (St = 0.3) results in an increase in the rate of spreading of the shear layer. Phase-averaged results indicate the formation of large toroidal vortices formed as a result of amplification of the column-mode instabilities that are excited at this frequency. On the other hand, the higher frequency actuation affects the initial shear-layer instability and interferes with the formation of the large-scale structures. Detailed integral azimuthal length scale analyses reveal that despite the absence of the axisymmetric toroids, the St = 0.9 case shows the dominance of the axisymmetric mode even at large distances from the nozzle exit. This indicates that flow control methods need not always have a visual signature of their influence on the system.

Control of High Subsonic Cavity Flow Using Plasma Actuators

Localized arc filament plasma actuators were used to control pressure fluctuations in a cavity with a depth of 12.7 mm and length-to-depth ratio of 4.86. The rear wall of the cavity is inclined 30 deg with respect to the upstream flow, and the cavity length is 61.7 mm. Five actuators were uniformly distributed along the span of the cavity, 1 mm upstream of the cavity leading edge. Experiments were conducted in a flow with a Mach number of 0.6 and a Reynolds number based on the cavity depth of . Forcing was conducted quasi-two-dimensionally (all actuators operated in phase) and three-dimensionally (actuators operated out of phase). The objective of the research was twofold: first, to demonstrate that the peak tone as well as the broadband pressure fluctuations can be suppressed in a strongly resonating cavity, and second, the resonance can be re-established and the peak tone as well as the broadband pressure fluctuations can be amplified in a weakly resonating cavity. Time-resolved pressure and particle-image-velocimetry measurements were used to assess the effectiveness of the actuators and to explore the physics of the flow. Although both quasi-two-dimensional and three-dimensional controls were successful in controlling the flow, the control was less sensitive to forcing frequency change in the latter in achieving the first objective. The results also showed that, although there are many forcing frequency options in achieving the first objective, the options are limited to frequencies near the dominant (even though weak) Rossiter modes in re-establishing the feedback in a weakly resonating cavity.

Control of oblique shock wave/boundary layer interactions using plasma actuators

Localized arc filament plasma actuators (LAFPAs) are used for shock wave/boundary layer interaction induced separation control in a Mach 2.3 flow. The boundary layer is fully turbulent with a Reynolds number based on the incompressible momentum thickness of 22,000 and shape factor of 1.37, and the impinging shock wave is generated by a 10° compression ramp. The LAFPAs are observed to have significant control authority over the interaction. The main effect is the displacement of the reflected shock and most of the interaction region upstream by approximately one boundary layer thickness (~5 mm). The initial goal of the control was to manipulate the low-frequency (St~0.03) unsteadiness associated with the interaction region. A detailed investigation of the effect of actuator placement, frequency, and duty cycle on the control authority indicates the actuators’ primary control mechanism is not the manipulation of low-frequency unsteadiness. Detailed measurements and analysis indicate that a modification to the boundary layer through heat addition by the actuators is the control mechanism, despite the extremely small power input of the actuators.

Parametric study of a Mach 1.3 cold jet excited by the flapping mode using plasma actuators

This paper describes an investigation into numerical and physical parameters influencing an ideally-expanded Mach 1.3 jet excited by the m=±1 flapping mode. The nozzle exit properties of the perfectly expanded jet include: ρjet=1.576kg/(m3), Tjet=224K, Re=1.1×106, and T0jet=Tambient=300K. The excitation is imposed by eight Localized Arc Filament Plasma Actuators (LAFPA) placed around the periphery of the circular nozzle exit. The reference controlled case considers the most amplified (jet column mode) frequency corresponding to a Strouhal number of 0.3 based on the diameter of the nozzle and jet velocity, with an actuator-imposed temperature of 1500K and a duty cycle of 20%. Relative to this reference, the effects of changing frequency, duty cycle and actuator model temperature are explored and results are compared with experimental data where available. The results are analyzed with several different quantitative and qualitative metrics, including time-averaged centerline decay and jet half-width as well as phase-averaged coherent structures. Raising the frequency affects the dynamics in several ways; the number of features observed in the phase-averaged data increases and the rate of decay of the centerline velocity is reduced. The alternating vortex ring interactions observed in the reference case are not distinct but are rather replaced by smaller structures, trends which are also observed in experiment. Lowering the Strouhal number increases mixing until a reversal occurs at St=0.1. The higher duty cycle exhibits strengthened coherent structures and slightly higher jet growth along the flapping plane, but the overall dynamics remain the same. The response of the jet is relatively insensitive to actuator temperature model within reasonable limits. The latter two studies, with different duty cycles and actuator temperatures, are consistent with previous analyses demonstrating that instability manipulation, rather than heat deposition is the primary mechanism of control.

The impulse response of a high-speed jet forced with localized arc filament plasma actuators

We present experimental and theoretical analyses of the response of high-speed, high-Reynolds-number, round jets to impulsive forcing with arc-filament-plasma actuators. The impulse response is obtained with forcing Strouhal numbers, based on the nozzle exit diameter and exit center line velocity, less than 0.1. The resulting phase-averaged near-field pressure signature displays a compact wave with a positive peak preceding a negative one, indicative of a large scale structure in the shear layer of the jet. Scaling laws derived by operating the jet at four subsonic Mach numbers are used to distinguish this hydrodynamic component of the phase-averaged jet response from the direct actuator noise. As the forcing frequency increases, the compact waves in the near-field pressure signal overlap each other, indicating interaction of the growing seeded structures. For this regime, the phase-averaged response is approximately replicated by linear superposition of the impulse response, thereby demonstrating the quasi-linearity of structure interaction. A novel application of linear parabolized stability theory yields a successful model of the impulse response.

Analysis of plasma-based flow control mechanisms through large-eddy simulations

High-fidelity simulations will become ever more important in the future if their use is routinely extended beyond engineering prediction to scientific analysis of the underlying physics. In particular, carefully conducted simulations can provide insight into aspects that are difficult if not impossible to explore in experiments. In this paper, we highlight such use of CFD to understand plasma-based flow control techniques, with emphasis on how the disturbances couple to the flowfield for actuators that are heat (as opposed to force) based. We present results with a relatively new type of actuator, the Nano-Second Dielectric Barrier Discharge (NS-DBD), which is formed by a flush mounted and embedded electrode combination excited by sharp (O(50) ns) pulses. A numerical model is presented and then applied to explore control of a stalled NACA 0015 airfoil at 15° angle of attack. These new results are assimilated with prior efforts on Localized Arc Filament Plasma Actuators (LAFPAs), to examine the differences in response of free versus bounded shear layers. It is shown that the initial manifestation of the disturbance occurs in the form of weak streamwise vortices. At the low levels of excitation of interest in scalable application, pulsing is essential for amplification in both types of shear layers. Hairpin-like structures characteristic of entrainment are also a common feature. Differences are evident however due to the no-slip condition of the boundary layer, where multiple induced counter-rotating vortices are observed prior to breakdown.

High-Speed and High-Reynolds-Number Jet Control Using Localized Arc Filament Plasma Actuators

A class of plasma actuators called localized arc filament plasma actuators for high-speed and high-Reynoldsnumber flow and acoustic control has been developed at the Gas Dynamics and Turbulence Laboratory. Over the past several years, these high-bandwidth (0 to 200 kHz) and individually controlled actuators have been used successfully to excite the jet shear layer, jet column, and azimuthal instabilities in high subsonic and supersonic jets. The focus of this paper is to provide detailed information and sample results highlighting the capabilities and potential of the actuators and the control technique formixing enhancement, noise mitigation, and flow and acoustic diagnostics. The jet, using three different nozzles, is operated over a large range of jet Mach numbers (0.9 to 1.65), stagnation temperature ratios (up to 2.5), and Reynolds numbers (0:2 10 to 1:65 10). Over this space of operating conditions, the jet is found to respond to control with a large range of forcing Strouhal numbers and azimuthalmodes. The results reveal that the jet flowfield and acoustic farfield can be dramatically altered, providing a powerful control tool in these practical high-speed and high-Reynolds-number jets.

Separation Control with Nanosecond-Pulse-Driven Dielectric Barrier Discharge Plasma Actuators

Abstract : The efficacy of dielectric barrier discharge (DBD) plasmas driven by high voltage (approximately 15 kV) repetitive nanosecond pulses approximately 100 ns FWHM) for flow separation control is investigated experimentally on an airfoil leading edge up to Re=1x106 (62 m/s). Unlike AC-DBDs, the nanosecond pulse driven DBD plasma actuator transfers very little momentum to the neutral air, but generates compression waves similar to localized arc filament plasma actuators. A complex pattern of quasi-planar and spherical compression waves is observed in still air. Measurements suggest that some of these compression waves are generated by discharge filaments that remain fairly reproducible pulse-to-pulse. The device performs as an active trip at high Re pre-stall angles of attack and provides perturbations that generate coherent spanwise vortices at post-stall. These coherent structures entrain freestream momentum thereby reattaching the normally separated flow to the suction surface of the airfoil. Coherent structures are identified at all tested frequencies, but values of F(subponent c, exponent +)=4-6 are most effective for control. Such devices which are believed to function through thermal effects could be an alternative to AC-DBD plasmas that rely on momentum addition.

Noise Control of a High Reynolds Number High Speed Heated Jet Using Plasma Actuators

Localized arc filament plasma actuators (LAFPAs) have been used to control the flow and far-field acoustics of high Reynolds number, high-speed unheated jets at the Gas Dynamics and Turbulence Laboratory. The jet facility consists of an axisymmetric jet of exit diameter 2.54 cm with different nozzle blocks and variable jet temperature in an anechoic chamber. The focus of this paper is on the effect of control on far-field noise in a high subsonic ( Mj = 0.9) jet over a wide range of temperatures. A total of sixteen combinations of forcing azimuthal modes ( m = 0, 1, 3, and ±4) and temperature ratios ( To/ Ta = 1.0, 1.5, 2.0, and 2.5) at a wide range of forcing frequencies were utilized to explore LAFPAs' effect on far-field noise. LAFPAs show significant noise reduction around the peak frequency in shallow angles and a small increase in higher frequencies. The level of reduction is lower and the level of increase is higher towards the sideline. Consistent with previous works, the results show that forcing with higher azimuthal modes produces greater noise reduction. LAFPAs produce large amplitude narrowband tones in this small jet that are believed to be less significant in larger jets. The impact of these forcing tones is isolated and discussed. Across the range of temperatures explored, the effectiveness of LAFPAs improves as temperature increases. Possible reasons for the increase in effectiveness are discussed.

Coherent structures in plasma-actuator controlled supersonic jets: Axisymmetric and mixed azimuthal modes

High-fidelity simulations are employed to study the effect of eight localized arc filament plasma actuators placed around the periphery of a Mach 1.3 converging-diverging nozzle exit. Emphasis is placed on understanding the coherent structures generated by axisymmetric (m = 0), flapping or first mixed (m = ±1) and second mixed (m = ±2) modes, which are excited at the jet column-mode frequency corresponding to a Strouhal number based on jet diameter of 0.3. Baseline (no control) and constant excitation (actuators on continuously) cases are also simulated. Comparisons with experimental results indicate that the computational model reproduces the main features induced by the actuators. Furthermore, the mean flow exhibits many similarities with the theoretical predictions of Cohen and Wygnanski [J. Fluid Mech. 176, 221 (1987)]. Overall, the results indicate a complex coherent structure generation, evolution, and disintegration process. For m = ±1, the phase-averaged flow reveals successive distorted elliptic vortex rings with axes in the flapping plane but alternating on either side of the jet axis. This generates a chain of structures each of which interacts with its predecessor on one side of the major plane and its successor on the other. Through self and mutual induction, the leading segment of each loop is pinched and passes through the previous ring before rapidly breaking up. The m = ±2 mode yields elliptic structures with major axes of successive rings being aligned with the two symmetry planes, which are orthogonal to each other. The minor axis side is pulled downstream faster than the rest of the structure because of the higher velocity near the jet centerline and self-induced effects, yielding a horse-shoe shape when viewed in profile. The m = 0 mode exhibits axisymmetric roll-up events, with vortex ribs in the braid regions connecting successive large coherent structures. The constant excitation (with largest energy input) and baseline cases are similar to each other, indicating that the direct effect of heating is negligible.

On factors influencing arc filament plasma actuator performance in control of high speed jets

Localized arc filament plasma actuators (LAFPAs) have been developed and used at The Gas Dynamics and Turbulence Laboratory for the purpose of controlling high-speed and high Reynolds number jets. The ability of LAFPAs for use in both subsonic and supersonic jets has been explored, and experiments to date have shown that these actuators have significant potential for mixing enhancement and noise control applications. While it has been established that the actuators manipulate instabilities of the jet, the exact nature of how the actuation couples to the flow is still unclear. All of the results previously reported have been based on a nozzle extension that has an azimuthal groove of 1 mm width and 0.5 mm depth along the inner surface approximately 1 mm upstream of nozzle extension exit. The ring groove was initially added to shield the plasma arcs from the high-momentum flow. However, the effect of the ring groove on the actuation mechanism is not known. To explore this effect, a new nozzle extension is designed, which relocates the actuators to the nozzle extension face and eliminates the ring groove. Schlieren images, particle image velocimetry and acoustic results of a Mach 0.9 jet of Reynolds number ~6.1 × 105 show similar trends and magnitudes with and without a ring groove. Thus, it is concluded that the ring groove does not play a primary role in the LAFPAs’ control mechanism. Furthermore, the effect of the duty cycle of the actuator input pulse on the LAFPAs’ control authority is investigated. The results show that the minimum duty cycle that provides complete plasma formation has the largest control over the jet.

Acoustic and flow fields of an excited high Reynolds number axisymmetric supersonic jet

An axisymmetric perfectly expanded Mach 1.3 jet, with a Reynolds number based on the nozzle exit diameter (ReD) of 1.1 × 106 and turbulent boundary layer at the nozzle exit, was excited using localized arc filament plasma actuators over a wide range of forcing Strouhal numbers (StDF). Eight actuators distributed azimuthally were used to excite azimuthal modes m = 0–3. Far-field acoustic, flow velocity and irrotational near-field pressure were probed with a three-fold objective: (i) to investigate the broadband far-field noise amplification reported in the literature at lower speeds and ReD using excitation of m = 0 at low StDF; (ii) to explore broadband far-field noise suppression using excitation of m = 3 at higher StDF; and (iii) to shed some light on the connection between the flow field and the far-field noise. The broadband far-field noise amplification observed is not as extensive in amplitude or frequency range, but still sufficiently large to be of concern in practical applications. Broadband far-field noise suppression of 4–5 dB at 30° polar angle peak frequency, resulting in approximately 2 dB attenuation in the overall sound pressure level, is achieved with excitation of m = 3 at StDF ~ 0.9. Some of the noteworthy observations and inferences are (a) there is a strong correlation between the far-field broadband noise amplification and the turbulence amplification; (b) far-field noise suppression is achieved when the jet is forced with the maximum jet initial growth rate frequency thus limiting significant dynamics of structures to a shorter region close to the nozzle exit; (c) structure breakdown and dynamic interaction seem to be the dominant source of noise; and (d) coherent structures dominate the forced jet over a wide range of StDF (up to ~ 1.31) with the largest and most organized structures observed around the jet preferred mode StDF.

Extremizing Feedback Control of a High-Speed and High Reynolds Number Jet

We present results of the development and application of extremizing feedback control to high-speed and high Reynolds number axisymmetric jets. In particular, we demonstrate control authority on the near-field pressure of a Mach 0.9 jet with a Reynolds number based on jet diameter of 7.8 ◊ 10 5 . Open-loop forcing experiments are presented wherein localized arc filament plasma actuators are shown to have two distinct effects on the near-field pressure, similar to their effect on the far-field acoustics reported earlier. At low forcing Strouhal numbers (StDF’s) near the jet column mode instability, a large amplification in the pressure fluctuations is observed. At higher StDF’s (close to the initial shear layer instability) a broad attenuation is observed in the near-field pressure fluctuations, especially in the axisymmetric mode. Previous experiments have shown that forcing the jet with these low and high frequencies result in jet mixing enhancement and far-field noise reduction, respectively. Two different gradient-free extremizing feedback control algorithms have been implemented, each of which can perform online minimum-seeking as well as maximumseeking. Both methods demonstrate fast convergence to the optimum followed by steady operation.

Development of localized arc filament RF plasma actuators for high-speed and high Reynolds number flow control

Recently developed localized arc filament plasma actuators (LAFPAs) have shown tremendous control authority in high-speed and high Reynolds number flow for mixing enhancement and noise mitigation. Previously, these actuators were powered by a high-voltage pulsed DC plasma generator with low energy coupling efficiency of 5–10%. In the present work, a new custom-designed 8-channel pulsed radio frequency (RF) plasma generator has been developed to power up to 8 plasma actuators operated over a wide range of forcing frequencies (up to 50 kHz) and duty cycles (1–50%), and at high energy coupling efficiency (up to 80–85%). This reduces input electrical power requirements by approximately an order of magnitude, down to 12 W per actuator operating at 10% duty cycle. The new pulsed RF plasma generator is scalable to a system with a large number of channels. Performance of pulsed RF plasma actuators used for flow control was studied in a Mach 0.9 circular jet with a Reynolds number of about 623,000 and compared with that of pulsed DC actuators. Eight actuators were distributed uniformly on the perimeter of a 2.54-cm diameter circular nozzle extension. Both types of actuators coupled approximately the same amount of power to the flow, but with drastically different electrical inputs to the power supplies. Particle image velocimetry measurements showed that jet centerline Mach number decay produced by DC and RF actuators operating at the same forcing frequencies and duty cycles is very similar. At a forcing Strouhal number near 0.3, close to the jet column instability frequency, well-organized periodic structures, with similar patterns and dimensions, were generated in the jets forced by both DC and RF actuators. Far-field acoustic measurements demonstrated similar trends in the overall sound pressure level (OASPL) change produced by both types of actuators, resulting in OASPL reduction up to 1.2–1.5 dB in both cases. We conclude that pulsed RF actuators demonstrate flow control authority similar to pulsed DC actuators, with a significantly reduced power budget.