Energy harvesting of a heaving and forward pitching wing with a passively actuated trailing edge

Siala, Firas; Liburdy, James A.

doi:10.1016/j.jfluidstructs.2015.05.007

Cited by 23 publications

(3 citation statements)

References 29 publications

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“…The hydrokinetic of the oscillating‐foil turbine was studied by Kinsey and Dumas 27 . Energy harvesting of heaving and pitching wings was investigated by Siala and Liburdy, 28 and a dual‐wing generator was studied in previous study 29…”

Section: Introductionmentioning

confidence: 99%

Modeling and analysis of a fully passive swinging sail wind turbine

2021

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Wind energy has been an attractive renewable energy source, and in recent decades, highly efficient horizontal axis wind turbines have been developed and successfully deployed. However, alternative designs for wind energy conversion have also been proposed. In previous studies, a novel swing sail design for wind energy harvesting was proposed and analyzed. This turbine harvests energy by pitching a sail, causing a mast to swing, which in turn drives a flywheel in a rectified rotational motion. The rotating flywheel is then used to drive an electric generator. The designed turbine was originally semiactive, while in the present study, the fully passive version of the turbine was proposed, and its performance was examined. The turbine consists of an oscillating sail attached to a reciprocally moving mast via a torsion spring, and the wind‐driven oscillatory motion is transformed into the rotational motion of a flywheel using a ratchet. Furthermore, a dry‐friction dynamometer was utilized as a simple way of extracting energy. The dynamical equations of the turbine were derived and were used to analyze the time response of the turbine. In the model, the correlations for the aerodynamic lift and drag forces for a flat plate were utilized. The results were validated using the computation fluid dynamics (CFD) simulation. The effects of various dynamical and geometric parameters of the turbine on the generated power and the turbine performance were also investigated.

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Section: Introductionmentioning

confidence: 99%

Modeling and analysis of a fully passive swinging sail wind turbine

2021

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“…It is desirable to maintain, as much as possible, a rather steady or prescribed blade loading in order to lower the fatigue risk and also suppress vibrations especially for helicopter blades. Various methods have been tried towards this objective, which in some cases could also result in increased annual energy production of the wind turbine, Barlas et [1], Krzysiak et al [2], Siala et al [3], Maldonaldo et al [4]. Collective or individual pitching of the wind turbine blades (cyclic pitch with a phase shift) was found to effectively reduce fatigue loads, Larsen et al [5], but rather sluggish to attenuate atmospheric turbulence effects.…”

Section: Introductionmentioning

confidence: 99%

Effects of an Oscillating Flap on the Main Airfoil Unsteady Lift in Grid Turbulence

Stapountzis

Barlas²,

Papageorgiou

et al. 2021

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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A wing of NACA 0015 profile and Aspect Ratio 2.4 fitted with a Trailing Edge Flap was tested in a wind tunnel for both smooth and turbulent flow conditions at a Re number 108000. The unsteady lift on the wing was measured with and without the flap. Two types of flap excitation were tried : One was of the "open loop" type in which the flap was subjected to sinusoidal pitching oscillations while the wing was set to a constant angle of attack. In the second, "closed loop" mode, the excitation signal fed into the flap originated from the unsteady lift of the wing itself. The phase lag between those signals was changed and it was found that it played a significant role in the suppression of the main wing unsteady lift.

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“…In an attempt to further improve energy harvesting efficiencies, the use of flexible surfaces has also received some attention in recent years [9,[32][33][34]. The study by Siala and Liburdy [33] experimentally evaluated the time-resolved aerodynamic load measurements in a combined forward pitching and heaving foil with a passively oscillating trailing edge. Under these conditions, they show that trailing edge flexibility enhances the mean power output by 14%.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Vortex Dynamics in the Near Wake of an Oscillating Flexible Foil

Siala

Totpal

Liburdy

2016

Journal of Fluids Engineering

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An experimental study was conducted to explore the effect of surface flexibility at the leading and trailing edges on the near-wake flow dynamics of a sinusoidal heaving foil. Midspan particle image velocimetry (PIV) measurements were taken in a closed-loop wind tunnel at a Reynolds number of 25,000 and at a range of reduced frequencies (k = fc/U) from 0.09 to 0.20. Time-resolved and phase-locked measurements are used to describe the mean flow characteristics and phase-averaged vortex structures and their evolution. Large-eddy scale (LES) decomposition and swirling strength analysis are used to quantify the vortical structures. The results demonstrate that trailing edge flexibility has minimal influence on the mean flow characteristics. The mean velocity deficit for the flexible trailing edge and rigid foils remains constant for all reduced frequencies tested. However, the trailing edge flexibility increases the swirling strength of the small-scale structures, resulting in enhanced cross-stream dispersion. Flexibility at the leading edge is shown to generate a large-scale leading edge vortex (LEV) for k ≥ 0.18. This results in a reduction in the swirling strength due to vortex interactions when compared to the flexible trailing edge and rigid foils. Furthermore, it is shown that the large-scale LEV is responsible for extracting a significant portion of energy from the mean flow, reducing the mean flow momentum in the wake. The kinetic energy loss in the wake is shown to scale with the energy content of the LEV.

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Energy harvesting of a heaving and forward pitching wing with a passively actuated trailing edge

Cited by 23 publications

References 29 publications

Modeling and analysis of a fully passive swinging sail wind turbine

Modeling and analysis of a fully passive swinging sail wind turbine

Effects of an Oscillating Flap on the Main Airfoil Unsteady Lift in Grid Turbulence

Characterization of Vortex Dynamics in the Near Wake of an Oscillating Flexible Foil

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