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

Koehler, Christopher; Liang, Zongxian; Gaston, Zachary; Wan, Hui; Dong, Haibo

doi:10.1242/jeb.069005

Cited by 110 publications

(109 citation statements)

References 45 publications

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“…Finally, the surfaces of the reconstructed model were represented by triangular cells (Figure 4d). This method was developed from the previous marker-based 3D surface reconstruction of insect flight [28] and its accuracy has been evaluated by comparing the positions of the fin tip, leading edge and trailing edge between the model and the experimental data. The reconstructed models were then imported as immersed moving boundaries in our in-house immersed-boundary-method-based computational fluid dynamics (CFD) solver.…”

Section: Viscous Modelmentioning

confidence: 99%

Hydrodynamic Performance of Aquatic Flapping: Efficiency of Underwater Flight in the Manta

et al. 2016

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Abstract:The manta is the largest marine organism to swim by dorsoventral oscillation (flapping) of the pectoral fins. The manta has been considered to swim with a high efficiency stroke, but this assertion has not been previously examined. The oscillatory swimming strokes of the manta were examined by detailing the kinematics of the pectoral fin movements swimming over a range of speeds and by analyzing simulations based on computational fluid dynamic potential flow and viscous models. These analyses showed that the fin movements are asymmetrical up-and downstrokes with both spanwise and chordwise waves interposed into the flapping motions. These motions produce complex three-dimensional flow patterns. The net thrust for propulsion was produced from the distal half of the fins. The vortex flow pattern and high propulsive efficiency of 89% were associated with Strouhal numbers within the optimal range (0.2-0.4) for rays swimming at routine and high speeds. Analysis of the swimming pattern of the manta provided a baseline for creation of a bio-inspired underwater vehicle, MantaBot.

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Section: Viscous Modelmentioning

confidence: 99%

Hydrodynamic Performance of Aquatic Flapping: Efficiency of Underwater Flight in the Manta

et al. 2016

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“…We took high-speed videos of freely flying hummingbirds using three synchronized Photron high-speed cameras. The hummingbird body and wing motions were then reconstructed using a joint-based hierarchical subdivision surface method [1,2]. As an example, Fig.…”

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confidence: 99%

Turning on a dime: Asymmetric vortex formation in hummingbird maneuvering flight

et al. 2016

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A pure yaw turn of a calliope hummingbird is investigated through high-speed photogrammetry, three-dimensional surface reconstruction, and computational fluid dynamics simulations. We took high-speed videos of freely flying hummingbirds using three synchronized Photron high-speed cameras. The hummingbird body and wing motions were then reconstructed using a joint-based hierarchical subdivision surface method [1,2]. As an example, Fig. 1(a) shows a high-speed image of the maneuvering hummingbird and Fig. 1(b) presents the corresponding reconstructed model. There are in total six strokes of this flight and they can be divided into three flying phases: a starting phase (first stroke), a maneuvering phase (second to fourth strokes), and a recovering phase (fifth and sixth strokes).A Cartesian grid based immersed boundary Navier-Stokes solver is used to simulate the unsteady flows around the body and wings of the bird [3,4]. We first look at the near wake structures by cutting two-dimensional flow slices along the hummingbird wing span. As shown in Fig. 1(c), leading edge vortex (LEV) structures at five flow slices can be observed for each wing. The contours of the LEV represent the normalized spanwise vorticity, which reveals the LEV strength. From the contour we observe that the LEV strength of the inner wing is greater than that of the outer wing. We further quantify the LEV circulation in the maneuvering phase. The results show that the inner wing produces 21% and 26% more average LEV circulation than the outer wing does during the downstrokes and upstrokes, respectively.The three-dimensional wake structures are identified by plotting the isosurface of Q criterion of the flow. As shown in Fig. 1(d), asymmetric wake structures between the inner and outer sides of the hummingbird body can be identified. Two new vortices, a shed trailing edge vortex (STEV) and a shed leading edge vortex (SLEV), can be identified at the outer side of the hummingbird body below the LEV. The LEV, tip vortex (TV), and STEV are connected to form a vortex ring near the outer wing tip region. Also, the LEV, SLEV, trailing edge vortex (TEV), and root vortex (RV) are connected to form another vortex ring. The two vortex rings form a unique dual-ring vortex structure at the outer side of the hummingbird body. In contrast, the LEV, TV, TEV, and RV are connected to form a single-ring vortex structure at the inner side of the hummingbird body.In order to better understand the wake topology and its effect on the aerodynamic performance, nondimensional pressure is plotted to indicate the low-pressure regions behind the wings of the

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“…Another feature is the anisotropic wing structure of dragonflies that results in different wing deformation depending on the orientation of surface loading. This feature supposedly helps reduce drag on the upstroking wings by decreasing projected area of the wings [18] [19]. There is ongoing research to study the passive wing deformation of dragonfly and other insects due to aerodynamic loading.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Analysis of a Bioinspired Multilayer Flexible Wing

Hefler¹,

Corti²,

Qiu³

2016

World Congress on Mechanical, Chemical, and Material Engineering

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-In this paper, aerodynamic characterization and performance analysis of a bioinspired multilayer flexible wing are discussed. Our membrane wing that consists of two separate layers can achieve better performance for applications utilizing flapping wing locomotion. This novel wing has two distinct features, the first, a passive shape deformation that is dependent on the direction of the aerodynamic loading on the wing surface, thus can reduce the negative lift of the upstroking wing without a complex mechanism required for active pitching. The other feature is the vortex trap mechanism realized by the separation of the layers at upstroke that results in a large scale vortex above the upstroking wing. This vortex can also generate additional lift by preserving a low pressure core. These features are inspired by the active wing shape control of birds, as well as an unsteady aerodynamic mechanism called clap and fling exhibited by several flying insect species. Such passive shape control on membrane wings could be utilized on micro air vehicles featuring a simple flapping mechanism design to achieve robustness and light weight.

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

Cited by 110 publications

References 45 publications

Hydrodynamic Performance of Aquatic Flapping: Efficiency of Underwater Flight in the Manta

Hydrodynamic Performance of Aquatic Flapping: Efficiency of Underwater Flight in the Manta

Turning on a dime: Asymmetric vortex formation in hummingbird maneuvering flight

Aerodynamic Analysis of a Bioinspired Multilayer Flexible Wing

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