Aerodynamic Bio-Mimetics of Gliding Dragonflies for  Ultra-Light Flying Robot

Obata, Akira; Shinohara, Shotarou; Akimoto, Kyohei; Suzuki, Kakeru; Seki, Miyuki

doi:10.3390/robotics3020163

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…Obata et al reported that corrugated wings exhibit higher wing performance than flat wings (Obata, et al, 2014). They mentioned that, when the corrugated wing exhibits high performance, the flow structure is characterized by the formation of vortex in V-shaped structures of corrugation (Obata, et al, 2014). We have not fully understood, however, the aerodynamic role of the vortices formed due to the V-shaped structure of the corrugated wing yet.…”

Section: Introductionmentioning

confidence: 94%

“…Most previous studies of the corrugated wings focus on the aerodynamic performance averaged over a long period of time, which may correspond to the performance of the gliding flight. Obata et al reported that corrugated wings exhibit higher wing performance than flat wings (Obata, et al, 2014). They mentioned that, when the corrugated wing exhibits high performance, the flow structure is characterized by the formation of vortex in V-shaped structures of corrugation (Obata, et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamic performance of dragonfly wing model that starts impulsively: how vortex motion works

Fujita

Iima

2023

JFST

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The cross-section of dragonfly wings has corrugated structures. In particular, the leading-edge side of the wing consists of V-shaped structures. According to previous studies, a corrugated wing may exhibit high aerodynamic performance at low Reynolds numbers (Re = O(10 3 )), and vortex dynamics associated with wing structure are expected to play an important role. We study the relationship between the wing structure and vortex dynamics by direct numerical simulations. It is known that, when a two-dimensional flat wing impulsively starts from a rest state, a coherent vortex called lambda vortex, which has the opposite sign to a leading-edge vortex (LEV), is generated and remains for a time interval. Our previous study suggests that, in the case of the corrugated wing, the lambda vortex collapses and is stuck inside V-shaped structures near the leading edge. The collapse of the lambda vortex was proposed as a key factor of high performance for the particular shape of the corrugated wing. In this paper, we investigate the relationship between vortex dynamics and high performance in a wider parameter range than in our previous studies. We analyse two corrugated models with different Reynolds numbers. It is revealed that the collapse of the lambda vortex is also the key to high performance for these cases.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Aerodynamic performance of dragonfly wing model that starts impulsively: how vortex motion works

Fujita

Iima

2023

JFST

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“…Detailed investigations 69,70,71 has been made for the dragonfly remarkable gliding capability; very different wings from dragonflies species and in spite of this, when they are tested in similar conditions (Re = 7,000; angle of attack 5º) the results presents small differences in flow patterns and vortex trains generation process; the corrugation wings structures (as they possess very noticeable corrugation over the first quarter-chord) and cruciform configuration allow that air circulates in the cavities between pleats creating areas of very low drag that aid the lift-generating airflow across the wing. Such corrugated wings during acceleration do not change the form of the outer flow and revealed good stability in unsteady wind conditions, providing superior flying characteristics for MAVs fixed wings in low Re flight, enabling a continued stable flight at low Re.…”

Section: Gliding Flightmentioning

confidence: 99%

Comparative Study of Wing’s Motion Patterns on Various Types of Insects on Resemblant Flight Stages

Neves

Barata

Manquinho

2015

AIAA Atmospheric Flight Mechanics Conference

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The behavioral flight capacitance, maneuverability and ability of insect's flight in recent years has become an active research that provided biological adaptative inspirations for the design and control of man-made MAVs and NAVs, essentially by identifying, exploiting and understand the basic principles of performance in-flight displayed by the insects. All qualities displayed in an insect flight, are determined by the functional capabilities of its flight muscles to produce force and work at a certain response speed as well as their efficiency in transforming chemical to mechanical energy; such energy is subsequently transmitted to their corrugated wings, were the performances of all flight muscles act and create part of wing's kinematics and deformation, being this the fundamental reason for the displayed maneuvers of all species of flying insects. This paper presents some summary considerations about all flying insects and is focused on the comparative skills displayed by those animals on resemblant flight stages.

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“…obs. ; Wakeling and Ellington, 1997;Gibo, 1981;Obata et al, 2014), so as to maintain altitude and speed when little wind is available to uphold gliding.…”

Section: Flight Speedmentioning

confidence: 99%

“…Gliding flight was set at a rate of 0.002904 W, which is the resting metabolic rate in a 330 mg globe skimmer (0.0024 W, May, 1979) increased by 20%. There is no reference for the metabolic rate for gliding in the literature, but as it is suggested to be near to that of resting (Gibo, 1981), but still has to account for energy required to angle the wings optimally (Wakeling and Ellington, 1997;Obata et al, 2014), we chose an increase of 20%.…”

Section: Energetic Flight Modelmentioning

confidence: 99%

Unraveling the World’s Longest Non-stop Migration: The Indian Ocean Crossing of the Globe Skimmer Dragonfly

Hedlund

Lehmann

et al. 2021

Front. Ecol. Evol.

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Insect migration redistributes enormous quantities of biomass, nutrients and species globally. A subset of insect migrants perform extreme long-distance journeys, requiring specialized morphological, physiological and behavioral adaptations. The migratory globe skimmer dragonfly (Pantala flavescens) is hypothesized to migrate from India across the Indian Ocean to East Africa in the autumn, with a subsequent generation thought to return to India from East Africa the following spring. Using an energetic flight model and wind trajectory analysis, we evaluate the dynamics of this proposed transoceanic migration, which is considered to be the longest regular non-stop migratory flight when accounting for body size. The energetic flight model suggests that a mixed strategy of gliding and active flapping would allow a globe skimmer to stay airborne for up to 230–286 h, assuming that the metabolic rate of gliding flight is close to that of resting. If engaged in continuous active flapping flight only, the flight time is severely reduced to ∼4 h. Relying only on self-powered flight (combining active flapping and gliding), a globe skimmer could cross the Indian Ocean, but the migration would have to occur where the ocean crossing is shortest, at an exceptionally fast gliding speed and with little headwind. Consequently, we deem this scenario unlikely and suggest that wind assistance is essential for the crossing. The wind trajectory analysis reveals intra- and inter-seasonal differences in availability of favorable tailwinds, with only 15.2% of simulated migration trajectories successfully reaching land in autumn but 40.9% in spring, taking on average 127 and 55 h respectively. Thus, there is a pronounced requirement on dragonflies to be able to select favorable winds, especially in autumn. In conclusion, a multi-generational, migratory circuit of the Indian Ocean by the globe skimmer is shown to be achievable, provided that advanced adaptations in physiological endurance, behavior and wind selection ability are present. Given that migration over the Indian Ocean would be heavily dependent on the assistance of favorable winds, occurring during a relatively narrow time window, the proposed flyway is potentially susceptible to disruption, if wind system patterns were to be affected by climatic change.

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Aerodynamic Bio-Mimetics of Gliding Dragonflies for Ultra-Light Flying Robot

Cited by 11 publications

References 8 publications

Aerodynamic performance of dragonfly wing model that starts impulsively: how vortex motion works

Aerodynamic performance of dragonfly wing model that starts impulsively: how vortex motion works

Comparative Study of Wing’s Motion Patterns on Various Types of Insects on Resemblant Flight Stages

Unraveling the World’s Longest Non-stop Migration: The Indian Ocean Crossing of the Globe Skimmer Dragonfly

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