In-Flight Demonstration of Stall Improvement Using a Plasma Actuator for a Small Unmanned Aerial Vehicle

Sekimoto, Satoshi; Kato, Hitoshi; Fujii, Kozo; Yanagawa, Hiroshi

doi:10.3390/aerospace9030144

Cited by 11 publications

(4 citation statements)

References 36 publications

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“…The use of morphing wing technology as a flow control technology has resulted in efficient aerodynamic designs [ 30 , 31 , 32 , 33 ]. Dynamic stall control is especially significant because it occurs in all aerospace applications, such as on UAVs [ 34 , 35 ], helicopter rotors [ 36 , 37 ], wind turbines [ 38 , 39 ], military aircraft [ 40 , 41 ], and others. Researchers have focused on tackling the dynamic stall phenomenon experienced by pitching oscillating airfoils for several years [ 42 , 43 , 44 , 45 , 46 ].…”

Section: Introductionmentioning

confidence: 99%

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

et al. 2023

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This paper investigates the effect of the Dynamically Morphing Leading Edge (DMLE) on the flow structure and the behavior of dynamic stall vortices around a pitching UAS-S45 airfoil with the objective of controlling the dynamic stall. An unsteady parametrization framework was developed to model the time-varying motion of the leading edge. This scheme was then integrated within the Ansys-Fluent numerical solver by developing a User-Defined-Function (UDF), with the aim to dynamically deflect the airfoil boundaries, and to control the dynamic mesh used to morph and to further adapt it. The dynamic and sliding mesh techniques were used to simulate the unsteady flow around the sinusoidally pitching UAS-S45 airfoil. While the γ − Reθ turbulence model adequately captured the flow structures of dynamic airfoils associated with leading-edge vortex formations for a wide range of Reynolds numbers, two broader studies are here considered. Firstly, (i) an oscillating airfoil with the DMLE is investigated; the pitching-oscillation motion of an airfoil and its parameters are defined, such as the droop nose amplitude (AD) and the pitch angle at which the leading-edge morphing starts (MST). The effects of the AD and the MST on the aerodynamic performance was studied, and three different amplitude cases are considered. Secondly, (ii) the DMLE of an airfoil motion at stall angles of attack was investigated. In this case, the airfoil was set at stall angles of attack rather than oscillating it. This study will provide the transient lift and drag at different deflection frequencies of 0.5 Hz, 1 Hz, 2 Hz, 5 Hz, and 10 Hz. The results showed that the lift coefficient for the airfoil increased by 20.15%, while a 16.58% delay in the dynamic stall angle was obtained for an oscillating airfoil with DMLE with AD = 0.01 and MST = 14.75°, as compared to the reference airfoil. Similarly, the lift coefficients for two other cases, where AD = 0.05 and AD = 0.0075, increased by 10.67% and 11.46%, respectively, compared to the reference airfoil. Furthermore, it was shown that the downward deflection of the leading edge increased the stall angle of attack and the nose-down pitching moment. Finally, it was concluded that the new radius of curvature of the DMLE airfoil minimized the streamwise adverse pressure gradient and prevented significant flow separation by delaying the Dynamic Stall Vortex (DSV) occurrence.

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Section: Introductionmentioning

confidence: 99%

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

et al. 2023

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“…The use of morphing wing technology as a flow control technique has resulted in efficient aerodynamic designs [15,[28][29][30]. Dynamic stall control is especially significant because it occurs in all aerospace applications, such as on UAVs [31,32], helicopter rotors [33,34], wind turbines [35,36] and military aircraft [37,38]. The effects of unsteady parameters, such as the oscillation amplitude, reduced frequency, Reynolds number and aerofoil kinematics (deformation, variable thickness etc.)…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the dynamic stall reduction on the UAS-S45 aerofoil using the optimised aerofoil method

Bashir,

Zonzini,

Longtin Martel

et al. 2023

Aeronaut. j.

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This paper investigates the effect of the optimised morphing leading edge (MLE) and the morphing trailing edge (MTE) on dynamic stall vortices (DSV) for a pitching aerofoil through numerical simulations. In the first stage of the methodology, the optimisation of the UAS-S45 aerofoil was performed using a morphing optimisation framework. The mathematical model used Bezier-Parsec parametrisation, and the particle swarm optimisation algorithm was coupled with a pattern search with the aim of designing an aerodynamically efficient UAS-45 aerofoil. The $\gamma - R{e_\theta }$ transition turbulence model was firstly applied to predict the laminar to turbulent flow transition. The morphing aerofoil increased the overall aerodynamic performances while delaying boundary layer separation. Secondly, the unsteady analysis of the UAS-S45 aerofoil and its morphing configurations was carried out and the unsteady flow field and aerodynamic forces were analysed at the Reynolds number of 2.4 × 106 and five different reduced frequencies of k = 0.05, 0.08, 1.2, 1.6 and 2.0. The lift ( ${C_L})$ , drag ( ${C_D})$ and moment ( ${C_M})\;$ coefficients variations with the angle-of-attack of the reference and morphing aerofoils were compared. It was found that a higher reduced frequencies of 1.2 to 2 stabilised the leading-edge vortex that provided its lift variation in the dynamic stall phase. The maximum lift $\left( {{C_{L,max}}} \right)$ and drag $\left( {{C_{D,max}}} \right)\;$ coefficients and the stall angles of attack are evaluated for all studied reduced frequencies. The numerical results have shown that the new radius of curvature of the MLE aerofoil can minimise the streamwise adverse pressure gradient and prevent significant flow separation and suppress the formation of the DSV. Furthermore, it was shown that the morphing aerofoil delayed the stall angle-of-attack by 14.26% with respect to the reference aerofoil, and that the ${C_{L,max}}\;$ of the aerofoil increased from 2.49 to 3.04. However, while the MTE aerofoil was found to increase the overall lift coefficient and the ${C_{L,max}}$ , it did not control the dynamic stall. Vorticity behaviour during DSV generation and detachment has shown that the MTE can change the vortices’ evolution and increase vorticity flux from the leading-edge shear layer, thus increasing DSV circulation. The conclusion that can be drawn from this study is that the fixed drooped morphing leading edge aerofoils have the potential to control the dynamic stall. These findings contribute to a better understanding of the flow analysis of morphing aerofoils in an unsteady flow.

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“…Separation delay using plasma actuators was demonstrated for airfoil stall conditions both in static [4,5] and dynamic conditions [6,7]. More recently, some in-flight tests for UAV vehicles were performed [8,9]. One should note that successful attempts to suppress separation using plasma actuators were performed either at extremely low flow velocities [4] or in stall conditions, when the boundary layer is laminar at the separation point [5,10].…”

Section: Introductionmentioning

confidence: 99%

Turbulent Boundary Layer Separation Control Using Magnetohydrodynamic Plasma Actuator

Kotvitskii,

Kazanskii,

Moralev

2023

Aerospace

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The pulse electric arc discharge in an external magnetic field is studied as a vortex generator in the subsonic boundary layer. A pulsed Ampere force induces a hairpin vortex near the wall; its structure depends on the relative direction of arc propagation and external flow velocity. The data presented in this article were obtained from parametric studies of vortex characteristics and their effects on the boundary layer profile at various actuator momentum coefficients (Cμ=1−30) and vortex sizes relative to the boundary layer thickness (D/δ=0.5−1.2). Also, the control of turbulent boundary layer separation on a bump at a flow velocity up to 50 m/s was attempted. An average shift of the separation line by 15% of the bump height was obtained at a flow velocity of 50 m/s and a total momentum coefficient of 0.6%.

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In-Flight Demonstration of Stall Improvement Using a Plasma Actuator for a Small Unmanned Aerial Vehicle

Cited by 11 publications

References 36 publications

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

Numerical investigation of the dynamic stall reduction on the UAS-S45 aerofoil using the optimised aerofoil method

Turbulent Boundary Layer Separation Control Using Magnetohydrodynamic Plasma Actuator

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