Flapping Wing Aerodynamics: Progress and Challenges

Platzer, Max F.; Jones, Kevin D.; Young, John; Lai, J.C.S.

doi:10.2514/1.29263

Cited by 448 publications

(135 citation statements)

References 61 publications

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“…This effect has been known since Knoller (1909) and Betz (1912) perceived that flapping a wing in a free stream flow resulted in an effective angle of attack with a normal force vector containing both lift and thrust components. This effect was experimentally demonstrated later by Katzmayr (1922) and revisited by Lai and Platzer in several papers published about the end of the twentieth century (see, e.g., [12]. The effect of inverted Kármán vortex street is used by slowly soaring birds for occasional increase in lift.…”

Section: How Do Birds Actually Generate Lift?mentioning

confidence: 90%

Aerodynamics of bird flight

Dvořák

2016

EPJ Web of Conferences

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Abstract. Unlike airplanes birds must have either flapping or oscillating wings (the hummingbird). Only such wings can produce both lift and thrust -two sine qua non attributes of flying.The bird wings have several possibilities how to obtain the same functions as airplane wings. All are realized by the system of flight feathers. Birds have also the capabilities of adjusting the shape of the wing according to what the immediate flight situation demands, as well as of responding almost immediately to conditions the flow environment dictates, such as wind gusts, object avoidance, target tracking, etc. In bird aerodynamics also the tail plays an important role. To fly, wings impart downward momentum to the surrounding air and obtain lift by reaction. How this is achieved under various flight situations (cruise flight, hovering, landing, etc.), and what the role is of the wing-generated vortices in producing lift and thrust is discussed.The issue of studying bird flight experimentally from in vivo or in vitro experiments is also briefly discussed.

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Section: How Do Birds Actually Generate Lift?mentioning

confidence: 90%

Aerodynamics of bird flight

Dvořák

2016

EPJ Web of Conferences

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“…Recently, this problem has attracted more focused attention due to its relevance to low-Reynolds-number flapping flight associated with micro air vehicles [1,2]. To understand the physical mechanisms of flapping flight, it is required to estimate the aerodynamic lift from unsteady velocity fields obtained by computational-fluid-dynamics codes and particle-image-velocimetry (PIV) measurements in wind tunnels [3][4][5][6][7][8][9][10].…”

Section: Nomenclaturesmentioning

confidence: 99%

Evaluation of Lift Formulas Applied to Low-Reynolds-Number Unsteady Flows

Wang

Zhang

et al. 2015

AIAA Journal

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Different lift decompositions into the elemental terms are compared based on direct numerical simulations of a flapping flat plate and a flapping rectangular wing at low-Reynolds-number flows. The simple lift formula is given as a useful approximate form that has the vortex force and local acceleration terms. The accuracy of the simple lift formula in lift estimation is quantitatively evaluated in comparison with the general force formulas based on the fully resolved two-and three-dimensional unsteady velocity fields and the planar velocity fields at several spanwise locations in simulated particle-image-velocimetry measurements. In addition, the mathematical connections between the different force formulas are discussed.

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“…Lehmann 15 published a study of the wing-wake interaction of wings in tandem configuration and contended that the aerodynamic efficiency can be enhanced by recovering energy from the wake. A further review of tandem and biplane wings was shown by Platzer et al 16 , where the authors observe that biplane configurations are not present in nature, possibly due to poor efficiency in hover flight.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Model for Tandem Flapping Wings

Faisal

Filippone

2016

AIAA Journal

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An aerodynamic model for tandem flapping wings is proposed. The model attempts to represent insects such as the dragonfly. Two advances are presented: the aerodynamic model with tandem wings flapping simultaneously, and the wing stroke optimization. The aerodynamic model accounts for the inflow effects of the front wing (fore-wing) on the rear wing (hind-wing). The stroke is optimized at two flight conditions (acceleration and level flight) by using a heuristic optimization procedure (particle swarming). The vector of the design variables consists of 28 independent parameters (14 per wing), each with a constrained range derived from the maximum available power, the flight muscle ratio and kinematics of real insects. The cost function is the propulsive efficiency coupled with constraints for flight stability. Prediction of the level flight efficiency is in agreement with the flight muscle efficiency. The maximum acceleration is found to be dependent on the size of the flight muscle. Finally, a study of the wing shape is presented for both level and accelerating flight conditions. = normalized chord c = mean chord length= rate of the wing rotation dr = wing section dt = time step D = drag f = frequency (motion frequency)

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Flapping Wing Aerodynamics: Progress and Challenges

Cited by 448 publications

References 61 publications

Aerodynamics of bird flight

Aerodynamics of bird flight

Evaluation of Lift Formulas Applied to Low-Reynolds-Number Unsteady Flows

Aerodynamic Model for Tandem Flapping Wings

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