Rotor Performance Enhancement Using Pulsed Plasma Actuation

Polonsky, Dor; Keisar, David; Greenblatt, David

doi:10.2514/1.j060342

Cited by 2 publications

(7 citation statements)

References 24 publications

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“…Consequently, the local reduced frequency 𝐹 + 𝑡 ≡ 𝑓 𝑚 𝑐/Ω𝑟 increases inboard of the tip. We surmise that the saturating effect observed at different physical frequencies also operates in a quasi two-dimensional sense along the outer span of the blade [17]. In other words, perturbations along the blade span excite the local shear layer in the same manner as if it were a separated airfoil shear layer.…”

Section: A Hover Performancementioning

confidence: 68%

“…The actuators were driven at 10 kV ptp and at a system resonance frequency: 𝑓 ion = 6 kHz. In order to maintain a reduced frequency range 1.3 ≤ 𝐹 + 𝑡 ≤ 2.8 [17] a pulse-modulation frequency 𝑓 𝑚 = 2 kHz was employed, with a 50% duty cycle. For all plasma actuation experiments, no attempt was made to introduce intracycle amplitude or frequency modulation, similar to that on airfoils [28,29],…”

Section: Experimental Methods and Data Acquisitionmentioning

confidence: 99%

“…The separated shear layer excitation on a rotor blade versus that on a two-dimensional airfoil are fundamentally different [17]. This difference is because the blade velocity varies with the rotor radius 𝑈 = Ω𝑟, and hence the reduced frequency, which we base on tip conditions for convenience, is not uniquely defined.…”

Section: A Hover Performancementioning

confidence: 99%

“…Active mechanical methods, such as trailing-edge flaps and variable-droop leading edges, often cause significant changes to the center of gravity and load, while frequently requiring intricate mechanical elements and control systems. In this research, we employ pulse-modulated dielectric barrier discharge (DBD) plasma actuators, ideally suited to rotor application due to their lightweight and high-frequency bandwidth [15][16][17][18][19]. In the past, DBD plasma actuators have been employed to attenuate the tonal noise from cavities [20,21], to reduce slat aerodynamic noise [22], and to control flow noise generated by cylinders [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…First, the collective angle of the blades is increased into the post-stall regime to achieve the maximum baseline thrust (but not Figure of Merit). Second, pulsed DBD plasma actuation is applied to attach the boundary layer and perfrom a simultaneous increase in thrust and decrease in rotor torque [17,19]. Third, the rotational speed is decreased to recover the original baseline thrust.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Polonsky¹,

Stalnov²,

Greenblatt³

2022

Preprint

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Noise reduction was achieved on a model helicopter rotor using pulsed dielectric barrier discharge (DBD) plasma actuators mounted at the blades' leading edges. The rotor was mounted on a bi-axial balance in an anechoic chamber, and the following three-point noise-reduction strategy was adopted: first, the blades' collective (geometric) angle was increased into the post-stall regime to achieve maximum baseline thrust; second, actuation was applied, increasing thrust and decreasing torque; third, the rotational speed was decreased to recover the original baseline thrust. This strategy resulted in an increase in the maximum Figure of Merit and a decrease in broadband and tonal noise components. Broadband and loading noise reduction, up to 3 dB, was due to boundary layer attachment, resulting in smaller and weaker turbulent eddies in the wake and the tip-vortex and, therefore, more minor turbulent surface pressure fluctuations. Noise reduction directivity associated with the blade passing frequency of up to 3 dB was consistent with Lowson's theory. Surprisingly, at most of the observer angles, both the plasma pulsation and ionization frequencies were not visible in the spectra. This directional acoustic signature was assumed to be due to the geometric mounting of the actuator and its effect on the boundary layer.

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Section: A Hover Performancementioning

confidence: 68%

Section: Experimental Methods and Data Acquisitionmentioning

confidence: 99%

Section: A Hover Performancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Polonsky¹,

Stalnov²,

Greenblatt³

2022

Preprint

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Rotor performance enhancement by alternating current dielectric barrier discharge plasma actuation

Zhao¹,

Wang²,

Yang³

et al. 2022

Plasma Sci. Technol.

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The experimental system was established to explore the plasma flow control effect for helicopter rotors in hover mode. With the plasma actuator applied at the leading edge of the rotor’s blades, AC-DBD (alternating current dielectric barrier discharge) plasma actuation was generated by a sinusoidal AC high voltage generator. By direct force measurement, the influence of actuation parameters on the rotor’s aerodynamic performance was investigated at the tip Reynolds numbers of 1.7×105. The AC-DBD actuation can delay the blade stall to more than 3° with about 20% increase in the thrust coefficient at the post-stall pitch. At a constant motor power driving the rotor, AC-DBD actuation could reduce the rotor’s torque at the stalled pitch and increase the rotational speed of the rotor. Also, AC-DBD actuation could maintain a relatively high hover efficiency of the rotor at large collective pitches. In a wide range of actuation parameters, the AC-DBD plasma actuation could improve the rotor’s aerodynamic performance at large blade pitches. High-speed photography of the tuft motion on the blade’s upper surface showed that the AC-DBD plasma actuation could promote the reattachment of the blade’s separation flow.

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Rotor Performance Enhancement Using Pulsed Plasma Actuation

Cited by 2 publications

References 24 publications

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Rotor performance enhancement by alternating current dielectric barrier discharge plasma actuation

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