Aerodynamic Analysis of a harmonically Morphing Flap Using a Hybrid Turbulence Model and Dynamic Meshing

Abdessemed, Chawki; Yao, Yufeng; Bouferrouk, Abdessalem; Narayan, Pritesh

doi:10.2514/6.2018-3813

Cited by 7 publications

(2 citation statements)

References 21 publications

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“…In a different experiment at a high Reynolds number of 1 million, Jodin et al [14] showed that a substantial reduction in flow instabilities could be obtained using a vibrating TEF, in addition to an increase in the aerodynamic efficiency, if the flap vibrations are set at optimal frequencies and amplitudes. The use of a harmonically morphing TEF was also explored numerically for both aerodynamic and aeroacoustic performance enhancements [15,16] at low AoAs. It was shown that up to a 3% increase in the aerodynamic efficiency could be obtained, together with a 1.5 dB reduction of tonal noise.…”

Section: Introductionmentioning

confidence: 99%

Near Stall Unsteady Flow Responses to Morphing Flap Deflections

Abdessemed

Yao

Bouferrouk

2021

Fluids

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The unsteady flow characteristics and responses of an NACA 0012 airfoil fitted with a bio-inspired morphing trailing edge flap (TEF) at near-stall angles of attack (AoA) undergoing downward deflections are investigated at a Reynolds number of 0.62 × 106 near stall. An unsteady geometric parametrization and a dynamic meshing scheme are used to drive the morphing motion. The objective is to determine the susceptibility of near-stall flow to a morphing actuation and the viability of rapid downward flap deflection as a control mechanism, including its effect on transient forces and flow field unsteadiness. The dynamic flow responses to downward deflections are studied for a range of morphing frequencies (at a fixed large amplitude), using a high-fidelity, hybrid RANS-LES model. The time histories of the lift and drag coefficient responses exhibit a proportional relationship between the morphing frequency and the slope of response at which these quantities evolve. Interestingly, an overshoot in the drag coefficient is captured, even in quasi-static conditions, however this is not seen in the lift coefficient. Qualitative analysis confirms that an airfoil in near stall conditions is receptive to morphing TEF deflections, and that some similarities triggering the stall exist between downward morphing TEFs and rapid ramp-up type pitching motions.

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Section: Introductionmentioning

confidence: 99%

Near Stall Unsteady Flow Responses to Morphing Flap Deflections

Abdessemed

Yao

Bouferrouk

2021

Fluids

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“…A hybrid RANS-LES technique was used to investigate the airfoil morphing aerodynamic performance with a deflecting TEF [ 70 , 71 ]. Morphing enhanced the lift-to-drag ratio by 6%.…”

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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Controlling Flow Separation on a Thick Airfoil Using Backward Traveling Waves

Akbarzadeh

Borazjani

2020

AIAA Journal

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Aerodynamic Analysis of a harmonically Morphing Flap Using a Hybrid Turbulence Model and Dynamic Meshing

Cited by 7 publications

References 21 publications

Near Stall Unsteady Flow Responses to Morphing Flap Deflections

Near Stall Unsteady Flow Responses to Morphing Flap Deflections

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

Controlling Flow Separation on a Thick Airfoil Using Backward Traveling Waves

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