Optical Measurement of the Deformation, Motion, and Generated Force of the Wings of a Moth, Mythimna Separata (Walker).

Sunada, Shigeru; Song, Deqiang; Meng, Xiannan; Wang, Hao; Zeng, Lijiang; Kawachi, Keiji

doi:10.1299/jsmeb.45.836

Cited by 23 publications

(19 citation statements)

References 17 publications

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“…18 and references therein). In the case of insects, however, the few available observations (especially for large species) report wingbeat frequencies far below the natural resonant frequencies (19)(20)(21)(22). Recent experiments using a selfpropelled model with large-flapping-amplitude elastic wings (12) are consistent with the latter, because the propulsive efficiency of the model peaks for a flapping frequency lower than the primary linear resonance of the wings.…”

mentioning

confidence: 91%

Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance

Ramananarivo

Godoy-Diana

Thiria

2011

Proc. Natl. Acad. Sci. U.S.A.

223

231

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Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observations pointing out this feature, the underlying mechanisms explaining how the elastic nature of the wings is related to propulsive efficiency remain unclear. Here we use an experiment with a self-propelled simplified insect model allowing to show how wing compliance governs the performance of flapping flyers. Reducing the description of the flapping wing to a forced oscillator model, we pinpoint different nonlinear effects that can account for the observed behavior-in particular a set of cubic nonlinearities coming from the clamped-free beam equation used to model the wing and a quadratic damping term representing the fluid drag associated to the fast flapping motion. In contrast to what has been repeatedly suggested in the literature, we show that flapping flyers optimize their performance not by especially looking for resonance to achieve larger flapping amplitudes with less effort, but by tuning the temporal evolution of the wing shape (i.e., the phase dynamics in the oscillator model) to optimize the aerodynamics. F lying animals have long since inspired admiration and fueled the imagination of scientists and engineers. Alongside biologists studying form and function of flapping flyers in nature (1, 2), the last decade has seen an impressive quantity of studies driven by engineering groups using new techniques to develop and study artificial biomimetic flapping flyers (3, 4). The widespread availability of high-speed video and in particular the merging of experimental methods borrowed from fluid mechanics into the toolbox of the experimental biologist have permitted to elucidate various key mechanisms involved in the complex dynamics of flapping flight (see, for example, refs. 5-7).A recent field of investigation concerns the efficiency of flapping flyers, the major interrogation being about how natural systems optimize energy saving together with performance enhancement. In particular, the passive role of wing flexibility to increase flight efficiency through the bending of flapping wings has attracted a lot of attention. It is commonly agreed that this efficiency enhancement comes from the particular shape of the bent wing, which leads to a more favorable repartition of the aerodynamic forces (see refs. 8 and 9 for an extensive review). For flying animals in air, such as insects, it has been proposed (10-12) that wing inertia should play a major role in competing with the elastic restoring force, compared to the fluid loading. The mechanism governing the propulsive performance of the flapping flyer can therefore be seen at leading order as a two-step process, where the instantaneous shape of the wings is determined by a structural mechanics problem that then sets...

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mentioning

confidence: 91%

Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance

Ramananarivo

Godoy-Diana

Thiria

2011

Proc. Natl. Acad. Sci. U.S.A.

223

231

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“…Photogrammetry also has advantages over the projected laser line method in which static lasers are used to project a fringe pattern onto flapping wings (Song et al, 2001;Sunada et al, 2002;Wang et al, 2003;Zeng et al, 1996;Zeng et al, 2000) as specific points on the wings cannot be tracked because of the fixed laser alignment.…”

Section: Introductionmentioning

confidence: 99%

“…Despite some recent quantitative analysis of the wings of tethered (Sunada et al, 2002;Walker et al, 2009a) and free-flying (Bergou et al, 2010;Walker et al, 2010) insects, there is still a lack of literature regarding detailed 3D measurements of wing deformation in both the span-wise and chord-wise directions. This is partially due to the small wing size, fast motion of the wings, and unpredictable movement of free-flying insects.…”

Section: Introductionmentioning

confidence: 99%

3D reconstruction and analysis of wing deformation in free-flying dragonflies

Koehler

Liang

Gaston

et al. 2012

Journal of Experimental Biology

110

101

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SUMMARYInsect wings demonstrate elaborate three-dimensional deformations and kinematics. These deformations are key to understanding many aspects of insect flight including aerodynamics, structural dynamics and control. In this paper, we propose a template-based subdivision surface reconstruction method that is capable of reconstructing the wing deformations and kinematics of free-flying insects based on the output of a high-speed camera system. The reconstruction method makes no rigid wing assumptions and allows for an arbitrary arrangement of marker points on the interior and edges of each wing. The resulting wing surfaces are projected back into image space and compared with expert segmentations to validate reconstruction accuracy. A least squares plane is then proposed as a universal reference to aid in making repeatable measurements of the reconstructed wing deformations. Using an Eastern pondhawk (Erythimus simplicicollis) dragonfly for demonstration, we quantify and visualize the wing twist and camber in both the chord-wise and span-wise directions, and discuss the implications of the results. In particular, a detailed analysis of the subtle deformation in the dragonflyʼs right hindwing suggests that the muscles near the wing root could be used to induce chord-wise camber in the portion of the wing nearest the specimenʼs body. We conclude by proposing a novel technique for modeling wing corrugation in the reconstructed flapping wings. In this method, displacement mapping is used to combine wing surface details measured from static wings with the reconstructed flapping wings, while not requiring any additional information be tracked in the high speed camera output. Supplementary material available online at

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“…Several previous studies have investigated the mesosurface morphological details of the wings of tethered [43,44] and free-flying [45,46] insects. However, these studies focused primarily on static wings.…”

Section: Quantification Of Wing Flexibilitymentioning

confidence: 99%

Learning from Nature: Unsteady Flow Physics in Bioinspired Flapping Flight

Dong¹,

Bode-Oke²,

Li³

2018

Flight Physics - Models, Techniques and Technologies

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There are few studies on wing flexibility and the associated aerodynamic performance of insect wings during free flight, which are potential candidates for developing bioinspired microaerial vehicles (MAVs). To this end, this chapter aims at understanding wing deformation and motions of insects through a combined experimental and computational approach. Two sets of techniques are currently being developed to make this integration possible: first, data acquisition through the use of high-speed photogrammetry and accurate data reconstruction to quantify the wing and body motions in free flight with great detail and second, direct numerical simulation (DNS) for force measurements and visualization of vortex structures. Unlike most previous studies that focus on the nearfield vortex formation mechanisms of a single rigid flapping wing, this chapter presents freely flying insects with full-field vortex structures and associated unsteady aerodynamics at low Reynolds numbers. Our chapter is expected to lead to valuable insights into the underlying physics about flow mechanisms of low Reynolds number flight in nature, which will have great significance to flapping-wing MAV design and optimization research in the future.

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Optical Measurement of the Deformation, Motion, and Generated Force of the Wings of a Moth, Mythimna Separata (Walker).

Cited by 23 publications

References 17 publications

Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance

Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance

3D reconstruction and analysis of wing deformation in free-flying dragonflies

Learning from Nature: Unsteady Flow Physics in Bioinspired Flapping Flight

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