Low Reynolds Number Flow Dynamics of a Thin Airfoil with an Actuated Leading Edge

Drost, Kevin J.; Linvog, Heather; Apte, Sourabh V.; Liburdy, James A.

doi:10.2514/6.2011-3904

Cited by 11 publications

(6 citation statements)

References 48 publications

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“…The wing is based on an existing physical model developed at Oregon State University for future experimental studies. 36,37 The chord length (c) is 20 cm, the thickness to chord ratio is 0.038, the actuator length to chord ratio is 0.3, and a span to chord ratio is 3.85. The airfoil has elliptical rounded edges with a height to length ratio of 1:5.…”

Section: B Passively Actuated Trailing Edgementioning

confidence: 99%

Low Reynolds Number Flow Dynamics of a Thin, Flat Airfoil with Elastically Mounted Trailing Edge

Apte

Liburdy

Visbal

2012

42nd AIAA Fluid Dynamics Conference and Exhibit

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Direct numerical simulations were performed to study the effect of an elastically mounted trailing edge actuator on the unsteady flow over a plunging, thin airfoil at Reynolds number of 14700 based on the chord length. The goal is to investigate potential benefits of flow-induced passive actuation of the trailing edge to the lift and drag characteristics of flapping MAV wings. The trailing edge, of 30% the chord length, is hinged to the wing using a torsion spring. It may undergo flow induced rotation resulting in dynamic variations in the airfoil shape. This trailing-edge spring assembly is modeled by simple, linear, torsion spring dynamics. A small parameter space varying the spring flexibility is explored to investigate its effect on the airfoil performance. Firstly, the second-order fictitious domain based finite volume approach by Apte et al. (J. Comp. Phys. 2009) was extended to model this fluid-structure interaction problem on a fixed, Cartesian mesh. Verification studies were conducted on a canonical test case of a spring-mounted cylinder to show good predictive capability. Secondly, flow over a plunging thin flat airfoil, at reduced frequency of 5.7 (10 Hz) and 5 • angle of attack was investigated with and without the actuation of the trailing edge. It was found that, spring natural frequencies higher than the plunging frequency result in the tailing edge actuation that leads to net increase in thrust. The phase difference between the leading and trailing edge motions was found to vary based on the spring flexibility and played a critical role in governing wing performance.

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Section: B Passively Actuated Trailing Edgementioning

confidence: 99%

Low Reynolds Number Flow Dynamics of a Thin, Flat Airfoil with Elastically Mounted Trailing Edge

Apte

Liburdy

Visbal

2012

42nd AIAA Fluid Dynamics Conference and Exhibit

Self Cite

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“…The idea of utilizing a flapping motion for energy generation was initially introduced by Wu in 1972 [3], and later, in 1981, McKinney and Delaurier pioneered the extraction of energy from the heaving and pitching motions of a fluid using a flapping foil [4]. Subsequently, extensive research has been conducted on optimizing the energy-harvesting capabilities of flapping foils via the investigation of motion parameters [1,5,6], geometric and viscous parameters [2,[7][8][9][10], and flow control methods [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Performance of an Oscillating Wing Energy Harvester Using a Leading-Edge Flap

Alam,

Sohn

2023

JMSE

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In this study, we investigated the power generation capability of an oscillating wing energy harvester featuring an actively controlled flap positioned at the wing’s leading edge. The findings revealed that attaching a leading-edge flap reduces fluid flow separation below the wing’s lower surface at the leading edge, resulting in smoother flow and increased velocity near the hinge region. The leading-edge flap increases the pressure difference across the wing’s surface, thereby enhancing the overall performance. In addition, the introduction of the leading-edge flap effectively elongates the wing’s effective projected length in the heaving direction, leading to increased thrust. We examined flap lengths ranging from 10% to 50% of the chord length, with the maximum pitch angles of the wing and flap varying from 75° to 105° and 30° to 55°, respectively. The optimal power generation was achieved using a flap length of 40% of the chord length, combined with maximum wing and flap pitch angles of 95° and 45°, respectively. These conditions yielded a 29.9% overall power output increase and a 20.2% efficiency improvement compared to the case without the leading-edge flap.

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“…Existing static studies of various leading-edge devices revealed that leading-edge flaps could improve an airfoil's performance at low Reynolds number [13][14][15][16][17][18]. The static lift characteristics of LECS were extensively studied across angles of attack from 0 • to 30 • and control surface deflection ranging from 0 • to ± 45 • [19].…”

Section: Introductionmentioning

confidence: 99%

Exploring the Impact of Rapidly Actuated Control Surfaces on Drone Aerodynamics

Panta

Marino

Fisher

et al. 2023

Drones

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This study investigates the use of rapidly actuated leading-edge and trailing-edge control surfaces to improve the control authority of small fixed-wing drones. Static and dynamic characteristics were investigated and presented in two separate papers. In this paper, the focus is on the dynamic effects observed from rapidly actuated 30% chord leading- or trailing-edge hinged control surfaces affixed to two flat-plate airfoils. Forces were resolved from surface pressure measurements and are augmented by PIV measurements, smoke flow visualization and analyses. The static study revealed that trailing-edge control surfaces exhibited higher effectiveness in producing time-averaged CL compared to leading-edge control surfaces. However, leading-edge control surfaces exhibit significantly less fluctuation in pressure and lift coefficients at fixed angles of attack and control surface deflections, indicating better stability. Unsteady aerodynamic effects of the airfoil at α=0∘ and “ramp” deflections of trailing- and leading-edge control surfaces from 0∘ to 40∘ with variations in actuation rates showed that CL peaks are approximately three to four times greater than static values for the case of the leading-edge control surface. This has significant implications for fixed-wing drone maneuverability and countering the effects of atmospheric turbulence.

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Low Reynolds Number Flow Dynamics of a Thin Airfoil with an Actuated Leading Edge

Cited by 11 publications

References 48 publications

Low Reynolds Number Flow Dynamics of a Thin, Flat Airfoil with Elastically Mounted Trailing Edge

Low Reynolds Number Flow Dynamics of a Thin, Flat Airfoil with Elastically Mounted Trailing Edge

Enhancing the Performance of an Oscillating Wing Energy Harvester Using a Leading-Edge Flap

Exploring the Impact of Rapidly Actuated Control Surfaces on Drone Aerodynamics

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