An Experimental Study on Lift Force Generation Resulting from Spanwise Flow in Flapping Wings

Hong, Young S.

doi:10.5139/ijass.2006.7.2.086

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…This can be seen in both Figures 18(b) and 19(b) where the curved frame for both cases provides a positive normal force while the straight wings of the same length and width lead to essentially zero normal force. This is consistent with the findings of Hong and Altman [9], who found that for a wing with spanwise camber, the magnitude of the positive force produced on the downstroke is larger than the negative normal force produced on the upstroke. The data in Figures 18(a) and 19(a) suggest that the spanwise camber does not apparently lead to axial force production for this particular case.…”

Section: Flapping Wing Micro Air Vehicle Bench Test Setupsupporting

confidence: 92%

“…Variation in the span during flight occurs in nature, with, for instance, Pennycuick [8] showing through video analysis that the span during the upstroke of a cormorant was approximately 70 percent of that for its downstroke. Hong and Altman [9] have shown that wings with spanwise camber demonstrate an ability to produce greater lift than similar straight wings. Analysis of flow velocity data captured through PIV demonstrates that during the downstroke the cambered wing produces more positive lift force than the straight wing, while during the upstroke the cambered wing produces less negative lift force than the straight wing.…”

Section: Photogrammetrymentioning

confidence: 99%

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Flapping Wing Micro Air Vehicle Bench Test Setup

Curtis¹,

Reeder

Svanberg³

et al. 2012

International Journal of Micro Air Vehicles

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The purpose of this research was to develop testing methods that can be used to determine the forces, moments, and deflections involved in flapping wing aerodynamics. To pursue the research, a flapping wing mechanism and wings with spans ranging from 9.1 inches to 12.1 inches were built. A variety of mechanisms, capable of, alternatively, purely flapping, flapping with pitch, and flapping with pitch and out-of-plane motion were conceptualized and drawn using solid modeling software. Two of the simpler designs, a single degree-of-freedom flapping mechanism and the two-degree of freedom flapping mechanism were fabricated using a rapid prototype 3-D printer, and sustained operation was demonstrated. A thrust stand and a six-component force balance were used to gather force data from the flapping-only mechanism, combined with a variety of wing shapes. Four high-speed cameras were used to capture the motion of the wings. To minimize intrusiveness an array of laser dots was projected onto the wing during flapping and photogrammetry software was used to analyze the images and determine a shape profile of the wing composed of a frame and membrane during flapping. While the focus of this research was on the bench test setup development, some insight into the influence of wing design on the forces acting on the mechanism was gained. NOMENCLATURE INTRODUCTIONTechnological advancements in many fields including micro-electronics, sensors, microelectromechanical systems, and micro-manufacturing, are leading to an increased role for small aerial vehicles, generally termed Micro Air Vehicles (MAVs). The expectation that vehicles the size of a small bird, or even an insect, can be built leads to new challenges and opportunities in experimental testing. On very small scales, there are expectations that a flapping wing design, like that of natural flyers, might be more efficient or at least might have lower observability than propeller-driven aircraft.As with all aircraft testing, scale can affect the performance of the vehicle, both due to aeroelasticity and Reynolds number effects. However, unlike traditional aircraft tests which are ideally carried out with large models in wind tunnels to minimize these effects, MAV testing requires small but precise measurement equipment for very small scales. One of the goals of the Air Vehicles Directorate of the Air Force Research Laboratory (AFRL) is to improve their ability to comprehensively test a variety of MAV designs. As part of that goal, a collaborative effort between the Air Force Institute of Technology (AFIT) and AFRL has been undertaken to improve research and develop test methodology specific to MAV testing. Herein, we document initial phases of our efforts to explore two facets of measurement technology which are important to those who develop, test, and compare original MAV designs. Indeed, variants of the techniques we explore herein might even prove useful in characterizing natural flyers.Our series of tests includes measurements and analysis of data acquired wi...

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Section: Flapping Wing Micro Air Vehicle Bench Test Setupsupporting

confidence: 92%

Section: Photogrammetrymentioning

confidence: 99%

Flapping Wing Micro Air Vehicle Bench Test Setup

Curtis¹,

Reeder

Svanberg³

et al. 2012

International Journal of Micro Air Vehicles

View full text Add to dashboard Cite

show abstract

“…1). Lift generation on the various strokes of a flat rigid plate have been studied by Hong et al [4].Assuming the wing starts from a maximum height position The wing's angle of attack changes from positive to negative. Fig .…”

Section: Lift Generation In Flapping Wing Flightmentioning

confidence: 99%

“…Fig . 2 shows the lift and thrust generation with respect to the phase of a flapping airfoil [4]. The wing starts at a point, labeled as 18°, and then proceeds to complete one full flap (traveling 360°) and returning to its starting position.…”

Section: Lift Generation In Flapping Wing Flightmentioning

confidence: 99%

Aerodynamic Analysis of Flapping Wing over Fixed Wing

Rumi¹,

Chattopadhyay²,

Salam³

2014

IJET

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“…Although flapping mechanisms are in existence, there is only a small amount of work completed in the area of flow visualization around flapping wings. Hong, Sun and Altman 5 performed PIV measurements on a flat plate undergoing flapping motions which captured shed vorticity and they attempted to correlate this vorticity to lift. Galiński and Żbikowski 10 designed a flapping wing mechanism with a spherical double Scotch yoke to imitate insect flight as a precursor to MAVs with flapping wings.…”

Section: Lift and Thrust Generation In Flapping Wing Flightmentioning

confidence: 99%

Force Measurements and Flow Visualization for a Flexible Flapping Wing Mechanism

Massey

Flick

Jadhav

2009

International Journal of Micro Air Vehicles

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This paper describes a series of experiments using a flapping wing mechanism. Force measurements were combined with high speed photography for two sets of flexible wings. The aerodynamic forces generated by flexible membrane type wings were measured using a two degree of freedom force balance constructed during the course of these experiments which measured the aerodynamic forces of lift and thrust. Lift and thrust measurements were acquired as the mechanism flapped the flexible wings for multiple cases, and the two most interesting conditions were explored in more detail. These two conditions consisted of a zero velocity free stream condition and a forward flight condition of 5 m/s. For these two conditions, high-speed video of the flapping wing was taken. The images from the video were also correlated with cycle averaged aerodynamic forces produced by the mechanism. Several observations were made regarding the behavior of flexible flapping wings that should aid in the design of future flexible flapping wing vehicles. In addition, flow visualization images were taken of the flapping wing under forward flight condition and flow field velocity vectors were calculated.

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An Experimental Study on Lift Force Generation Resulting from Spanwise Flow in Flapping Wings

Cited by 9 publications

References 7 publications

Flapping Wing Micro Air Vehicle Bench Test Setup

Flapping Wing Micro Air Vehicle Bench Test Setup

Aerodynamic Analysis of Flapping Wing over Fixed Wing

Force Measurements and Flow Visualization for a Flexible Flapping Wing Mechanism

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