Plasma-Based Dynamic Stall Control and Modeling on an Aspect-Ratio-One Wing

Troyer, Tim De; Hasin, David; Keisar, David; Santra, Srimanta; Greenblatt, David

doi:10.2514/1.j060933

Cited by 10 publications

(7 citation statements)

References 66 publications

(139 reference statements)

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“…First, the ionization frequency can be increased by varying the load impedance or redesigning the bridge and transformer cascade electronics. Second, studies on a finite wing show that the pulsation frequency can be improved, by up to a factor of 25, without any loss in separation control effectiveness [41].…”

Section: B Acoustic Signaturementioning

confidence: 99%

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: B Acoustic Signaturementioning

confidence: 99%

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Polonsky¹,

Stalnov²,

Greenblatt³

2022

Preprint

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“…The Goman-Khrabrov (GK) model is a first-order model that is gaining more and more attention within the fluid dynamics community, especially for closed-loop flow control applications, such as lift hysteresis reduction during pitching manoeuvres (Williams et al 2015) and gust load alleviation (Williams & King 2018;Sedky, Jones & Lagor 2020). Recent efforts towards the enhancement of the GK model include the work of An et al (2021), who estimated the instantaneous lift coefficient of a pitching aerofoil by assimilating the predictions of a GK model with limited surface pressure measurements, and the studies of Williams et al (2019) andDe Troyer et al (2022), who extended the formulation of the GK model to account for active flow control by slot blowing and plasma actuation, respectively. Finally, Ayancik & Mulleners (2022) proposed to revisit and generalise the GK model by replacing its empirical parameters with physics-based time constants.…”

Section: Introductionmentioning

confidence: 99%

“…(2019) and De Troyer et al. (2022), who extended the formulation of the GK model to account for active flow control by slot blowing and plasma actuation, respectively. Finally, Ayancik & Mulleners (2022) proposed to revisit and generalise the GK model by replacing its empirical parameters with physics-based time constants.…”

Section: Introductionmentioning

confidence: 99%

Modelling the unsteady lift of a pitching NACA 0018 aerofoil using state-space neural networks

Damiola,

Decuyper,

Runacres

et al. 2024

J. Fluid Mech.

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The development of simple, low-order and accurate unsteady aerodynamic models represents a crucial challenge for the design optimisation and control of fluid dynamical systems. In this work, wind tunnel experiments of a pitching NACA 0018 aerofoil conducted at a Reynolds number $Re = 2.8 \times 10^5$ and at different free-stream turbulence intensities are used to identify data-driven nonlinear state-space models relating the time-varying angle of attack of the aerofoil to the lift coefficient. The proposed state-space neural network (SS-NN) modelling technique explores an innovative methodology, which brings the flexibility of artificial neural networks into a classical state-space representation and offers new insights into the construction of reduced-order unsteady aerodynamic models. The work demonstrates that this technique provides accurate predictions of the nonlinear unsteady aerodynamic loads of a pitching aerofoil for a wide variety of angle-of-attack ranges and frequencies of oscillation. Results are compared with a modified version of the Goman–Khrabrov dynamic stall model. It is shown that the SS-NN methodology outperforms the classical semi-empirical dynamic stall models in terms of accuracy, while retaining a fast evaluation time. Additionally, the proposed models are robust to noisy measurements and do not require any pre-processing of the data, thus involving only a limited user interaction. Overall, these features make the SS-NN technique an excellent candidate for the construction of accurate data-driven models from experimental fluid dynamics data, and pave the way for their adoption in applications entailing design optimisation and real-time control of systems involving lift.

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“…The study of pitching wings is crucial for the design and development of rotary and flapping wing configurations [1][2][3]. Recent interest in the development of smallscale unmanned aerial vehicles (UAVs) and micro aerial vehicles (MAVs) is sparking an increasing interest in the unsteady aerodynamics of low aspect ratio (AR) wings at low Reynolds numbers [4] and in the construction of reduced-order models thereof [5][6][7]. The aerodynamic forces on the pitching wing in air at low altitude depend upon a range of geometrical (wing profile, aspect ratio, pitch angle, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…In the case of low aspect ratio (LAR) wings, which are generally defined as an aspect ratio below 3 [28], the lift force is strongly dominated by the tip vortices and their interaction with the DSV [4,19,26]. In addition, there is a limited number of studies for LAR wings with conventional (non-flat-plate) wing profiles [4] such as the NACA-0018 used in this work. Such profiles could be more interesting for use in UAVs and MAVs [29,30].…”

Section: Introductionmentioning

confidence: 99%

Unsteady Aerodynamic Lift Force on a Pitching Wing: Experimental Measurement and Data Processing

et al. 2023

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This work discusses the experimental challenges and processing of unsteady experiments for a pitching wing in the low-speed wind tunnel of the Vrije Universiteit Brussel. The setup used for unsteady experiments consisted of two independent devices: (a) a position control device to steer the pitch angle of the wing, and (b) a pressure measurement device to measure the aerodynamic loads. The position control setup can pitch the wing for a range of frequencies, amplitude, and offset levels. In this work, a NACA-0018 wing profile was used with an aspect ratio of 1.8. The position control and the pressure measurement setups operate independently of each other, necessitating advanced signal processing techniques to synchronize the pitch angle and the lift force. Furthermore, there is a (not well-documented) issue with the (sampling) clock frequency of the pressure measurement setup, which was resolved using a fully automated spectral analysis technique. The wing was pitched using a simple harmonic sine excitation signal at eight different offset levels (between 6° and 21°) for a fixed amplitude variation (std) of 6°. At each offset level, the wing was pitched at five different frequencies between 0.1 Hz and 2 Hz (that correspond to reduced frequencies k ranging from 0.006 to 0.125). All the experiments were conducted at a fixed chord-based Reynolds number of 2.85 × 105. The choice of operating parameters invokes the linear and nonlinear behavior of the wing. The linear unsteady measurements agreed with the analytical results. The unsteady pressure measurements at higher offset levels revealed the nonlinear aerodynamic phenomenon of dynamic stall. This confirms that a nonlinear and dynamic model is required to capture the salient characteristics of the lift force on a pitching wing.

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Plasma-Based Dynamic Stall Control and Modeling on an Aspect-Ratio-One Wing

Abstract: with details of the nature of the infringement. We will investigate the claim and if justified, we will take the appropriate steps.

Cited by 10 publications

References 66 publications

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Noise Reduction on a Model Helicopter Rotor using DBD Plasma Actuators

Modelling the unsteady lift of a pitching NACA 0018 aerofoil using state-space neural networks

Unsteady Aerodynamic Lift Force on a Pitching Wing: Experimental Measurement and Data Processing

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