Minimum induced power requirements for flapping flight

Recent i n terest in the development of micro-airvehicles (MAVs) has led to a renewed interest in apping-wing propulsion due to the relatively poor eciencies of conventional propellers at these small scales. In the present study apping-wing con gurations found numerically to produce high propulsive-e ciencies are investigated experimentally. Several models of varying scales and complexity are developed and tested i n a l o w-speed wind-tunnel. The variation in scale of the models provides some insight i n to the rather severe Reynolds number e ects, and the development o f the smaller models provides an introduction into the di culties in the design, manufacture and testing of small-scale vehicles.The thrust is measured directly and compared with numerical predictions, with variations in the apping motion, aspect-ratio and scale. Measured thrust for the larger model compares well with the numerical predictions both qualitatively and quantitatively over most of the parameter-space, however, the smaller model, with approximately half the chord-length and a somewhat di erent apping motion, produces drastically di erent performance, indicating the presence of massive o w separation. The presented results indicate the necessity to better understand, and ultimately to utilize, ow separation in the design of successful apping-wing MAVs.

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Section: Introductionmentioning

confidence: 99%

Flapping-wing propulsion for a micro air vehicle

Platzer

Jones

2000

38th Aerospace Sciences Meeting and Exhibit

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“…More recently, the problem of apping foil propulsion has been considered by L i u 17 18 using vortex lattice and panel methods, by Send 19 20 using linearized theory and by Hall and Hall 21 and Hall et al 22 using vortex lattice methods. Jones et al 7 compared wake structures behind apping wings experimentally photographed and numerically predicted, and demonstrated that the formation and evolution of these unsteady wakes is essentially an inviscid phenomenon over a broad range of Strouhal numbers.…”

Section: Introductionmentioning

confidence: 99%

An experimental and numerical investigation of flapping-wing propulsion

Platzer

Jones

1999

37th Aerospace Sciences Meeting and Exhibit

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Flapping-wing propulsion is investigated experimentally and numerically with direct comparisons between experimental and numerical thrust measurements for several geometrically simple con gurations. Numerical simulations are performed using linear theory, and a previously developed, unsteady panel method that models one or two independently moving airfoils with three-degrees of freedom and non-linear deforming wakes. Experiments are carried out in the Naval Postgraduate School 5 0 5 0 low-speed tunnel. A apping mechanism that approximates the two-dimensional motions modeled by the panel code is suspended with cables in the wind tunnel, and thrust measurements are made by measuring the streamwise displacement of the model using a laser range-nder. The experimental apping mechanism utilizes variable aspectratio wings and optional tip plates to investigate the e ect of three-dimensionality. The device aps two airfoils, each with two degrees of freedom and adjustable pitch and plunge amplitudes, and additional stationary wings may be attached up and/or downstream of the apping wings to investigate interference e ects. Nomenclature b = wing span c = c hord length C d = drag coe cient per unit span, D=(q 1 c) C l = lift coe cient per unit span, L=(q 1 c) C m = moment coe cient per unit span, M=(q 1 c 2 )

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“…Others, such as Hall and Hall 7 and Wang, 5 have approached the problem from a different viewpoint by taking well-developed computer models of flapping flight and trying to predict optimum flapping parameters. In nature, flapping frequency selection must be based on biology and physics.…”

Section: Biology-based Workmentioning

confidence: 99%

Object-Oriented Unsteady Vortex Lattice Method for Flapping Flight

Fritz

Long

2004

Journal of Aircraft

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The unsteady vortex lattice method is used to model the oscillating plunging, pitching, twisting, and flapping motions of a finite-aspect-ratio wing. Its potential applications include design and analysis of small unmanned air vehicles and in the study of the high-frequency flapping flight of birds and other small flyers. The results are verified by theory and, in the plunging and pitching cases, by experimental data. The model includes free-wake relaxation, vortex stretching, and vortex dissipation effects and is implemented using object-oriented computing techniques. The results show that the method is capable of accurately simulating many of the features of complex flapping flight.

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Minimum induced power requirements for flapping flight

Cited by 86 publications

References 10 publications

Flapping-wing propulsion for a micro air vehicle

Flapping-wing propulsion for a micro air vehicle

An experimental and numerical investigation of flapping-wing propulsion

Object-Oriented Unsteady Vortex Lattice Method for Flapping Flight

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