The Relationship Between Dragonfly Wing Structure and Torsional Deformation

Sunada, Shigeru; Zeng, Lijiang; Kawachi, Keiji

doi:10.1006/jtbi.1998.0678

Cited by 96 publications

(58 citation statements)

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“…A similar picture might appear for aerodynamic effects due to more subtle changes in wing kinematics such as wing torsion, flexing, and changes in wing camber during flight (Song et al, 2001;Sunada et al, 1998), including effects due to corrugation of dragonfly wings (Kesel, 2000). Wing flexing, for example, has been discussed as a modification of the clapand-fling termed the 'clap-and-peel', which might alter force production during the fling part of the wing motion (Ellington, 1984b).…”

Section: Discussionmentioning

confidence: 78%

The fluid dynamics of flight control by kinematic phase lag variation between two robotic insect wings

Maybury

Lehmann

2004

Journal of Experimental Biology

151

124

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Functionally four-winged insects such as dragon-and damselflies use a large variety of wingbeat kinematics to produce and control aerodynamic forces for flight (Alexander, 1984;Azuma et al., 1985;Azuma and Watanabe, 1988;Chadwick, 1940;Grodnitsky and Morozov, 1992;Reavis and Luttges, 1988;Rüppell, 1989;Rüppell and Hilfert, 1993;Sato and Azuma, 1997;Somps and Luttges, 1985;Wakeling, 1993;Wakeling and Ellington, 1997;Wang et al., 2003;Weis-Fogh, 1967). The neuromuscular system allows these animals to actively manipulate many aspects of wing motion such as stroke amplitude, stroke frequency, the angle of attack and stroke plane (Norberg, 1975;Rüppell, 1989), but also to actively control the timing between the fore-and hindwing stroke cycles (kinematic phase relationship, Alexander, 1984;Azuma and Watanabe, 1988;Clark, 1940;Grodnitsky and Morozov, 1992;May, 1995;Sato and Azuma, 1997; Simmons, 1977a,b;Wakeling and Ellington, 1997;Wang et al., 2003). Thus dragonflies and damselflies differ significantly from other four-winged insect species such as butterflies, bees, wasps and ants, whose fore-and hindwings always beat in phase, due to a sophisticated joint that mechanically couples the motion of both wings throughout the entire stroke cycle (Gorb, 2001). Other insects of more primitive orders, such as locusts, lie somewhere between both extremes; in locust, the stroke-phase relationship seems to be highly consistent, with little variation during flight control (Chadwick, 1953;Weis-Fogh, 1956;Wilson, 1968;Wortmann and Zarnack, 1993). Cooter and Baker (1977) reconstructed wing motion of freely flying locust Locusta migratoria and found a fixed phase relationship between their fore-and hindwings in which the forewing slightly leads by approximately 61°.In contrast, dragonflies vary the phase relationship between ipsilateral fore-and hindwings with different behaviors (Norberg, 1975;Reavis and Luttges, 1988;Wakeling and Ellington, 1997;Wang et al., 2003). Three categories of phase relationship between fore-and hindwing have been established: phase-shifted stroking, counterstroking and parallel stroking. A highly consistent characteristic for the Insects flying with two pairs of wings must contend with the forewing wake passing over the beating hindwing. Some four-winged insects, such as dragonflies, move each wing independently and therefore may alter the relative timing between the fore-and hindwing stroke cycles. The significance of modifying the phase relationship between fore-and hindwing stroke kinematics on total lift production is difficult to assess in the flying animal because the effect of wing-wake interference critically depends on the complex wake pattern produced by the two beating wings. Here we investigate the effect of changing the fore-and hindwing stroke-phase relationship during hovering flight conditions on the aerodynamic performance of each flapping wing by using a dynamically scaled electromechanical insect model. By varying the relative phase difference between fore-and hindwing stroke cycles we...

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Section: Discussionmentioning

confidence: 78%

The fluid dynamics of flight control by kinematic phase lag variation between two robotic insect wings

Maybury

Lehmann

2004

Journal of Experimental Biology

151

124

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“…That road, so far, has been virtually untraveled with no compelling work to be cited prior to the authors'. Only two previous and praiseworthy attempts at revealing the modes and modeshapes of an insect wing were made by two independent researchers [22,23]; both on dragonfly wings. Each missed, or at least failed to communicate, the potential significance that eigenstructure may play in insect wing design and flight.…”

Section: Previous Workmentioning

confidence: 99%

Experimental Structural Dynamic Characterization of the Hawkmoth (Manduca Sexta) Forewing

Norris

Palazotto

Cobb

2013

International Journal of Micro Air Vehicles

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While many bio-inspired flapping wing micro air vehicle wing designs continue to be conceived and studied in earnest, a general consensus of which physical attributes of the biological entity are important for flight is still at-large. It is proposed herein that the eigenstructure of the wing should figure prominently among rigorous engineering metrics for guiding flapping wing micro air vehicle wing designs at the scales of large insects. With virtually no compelling work done in this area to date, the method and results of system identification tests for the forewings of a representative sample of hawkmoth (Manduca Sexta) are presented, revealing the underlying structural nature of this incredibly agile flyer's wings. Despite their inherent biological variability, these wings show very little variability in eigenstructure which may suggest it as a critical attribute for robust flight. Further supporting this hypothesis, the wings of four other insect species are briefly examined and show remarkable similarity with the hawkmoth wing's eigenstructure. INTRODUCTIONWhile the lure of the micro air vehicle (MAV) stems from its promise of operational capabilities that have been well documented [1,2,3,4], the attraction of the MAV within the research community is at least partly attributable to its low cost of entry into its field of study. Indeed, the large and expensive R&D infrastructure associated with larger scale and conventional aircraft development can be reduced to small indoor flight arenas, bench top engineering equipment and instrumentation, as well as the vast and affordable computing space offered by desktop computers, as illustrated in [5]. Arguably, it has been this ease of entry that has enabled the worldwide explosion in MAV related research over the past 10-15 years [6]. As a review of literature will reveal, from the first coining of "MAV" by Francis and McMichael [1], the locus of MAV related flight research quickly migrated toward bio-inspired wing designs and almost exclusively to flapping wing designs for hummingbird-size and smaller variants to include larger species of flying insect. While there are physical and operational arguments to reject more conventional fixed or rotary wing designs at MAV scales, perhaps the most compelling reason for partiality toward flapping wings is the perception that conceiving a design capable of rivaling the elegance of the solution that nature has already provided for flight at small scales is unlikely. Though this is intuitively compelling, bio-inspired design is not without fault.This paper briefly presents a case for tempering MAV flight researchers' zeal for bio-inspired wing design with a consideration of those features of natural design that may be important, if not required, for successful flapping flight, especially at large insect scales. This consideration naturally leads to an argument for why the eigenstructure of the insect wing, having neither skeletal nor musculature features, should figure prominently among MAV wing design parameters....

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“…caused torsion and marked ventral spanwise bending of the wings, which could have important implications for the structural mechanics and aerofoil design of dragonfly wings (Kesel, 2000;Sunada et al, 1998;Wootton et al, 1998).…”

Section: Unloaded Upstrokes In Free-flying Dragonfliesmentioning

confidence: 99%

Dragonfly flight: free-flight and tethered flow visualizations reveal a diverse array of unsteady lift-generating mechanisms, controlled primarilyviaangle of attack

Thomas

Taylor

Srygley

et al. 2004

Journal of Experimental Biology

282

208

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SUMMARY Here we show, by qualitative free- and tethered-flight flow visualization,that dragonflies fly by using unsteady aerodynamic mechanisms to generate high-lift, leading-edge vortices. In normal free flight, dragonflies use counterstroking kinematics, with a leading-edge vortex (LEV) on the forewing downstroke, attached flow on the forewing upstroke, and attached flow on the hindwing throughout. Accelerating dragonflies switch to in-phase wing-beats with highly separated downstroke flows, with a single LEV attached across both the fore- and hindwings. We use smoke visualizations to distinguish between the three simplest local analytical solutions of the Navier–Stokes equations yielding flow separation resulting in a LEV. The LEV is an open U-shaped separation, continuous across the thorax, running parallel to the wing leading edge and inflecting at the tips to form wingtip vortices. Air spirals in to a free-slip critical point over the centreline as the LEV grows. Spanwise flow is not a dominant feature of the flow field – spanwise flows sometimes run from wingtip to centreline, or vice versa –depending on the degree of sideslip. LEV formation always coincides with rapid increases in angle of attack, and the smoke visualizations clearly show the formation of LEVs whenever a rapid increase in angle of attack occurs. There is no discrete starting vortex. Instead, a shear layer forms behind the trailing edge whenever the wing is at a non-zero angle of attack, and rolls up, under Kelvin–Helmholtz instability, into a series of transverse vortices with circulation of opposite sign to the circulation around the wing and LEV. The flow fields produced by dragonflies differ qualitatively from those published for mechanical models of dragonflies, fruitflies and hawkmoths, which preclude natural wing interactions. However, controlled parametric experiments show that, provided the Strouhal number is appropriate and the natural interaction between left and right wings can occur, even a simple plunging plate can reproduce the detailed features of the flow seen in dragonflies. In our models, and in dragonflies, it appears that stability of the LEV is achieved by a general mechanism whereby flapping kinematics are configured so that a LEV would be expected to form naturally over the wing and remain attached for the duration of the stroke. However, the actual formation and shedding of the LEV is controlled by wing angle of attack, which dragonflies can vary through both extremes, from zero up to a range that leads to immediate flow separation at any time during a wing stroke.

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The Relationship Between Dragonfly Wing Structure and Torsional Deformation

Cited by 96 publications

References 0 publications

The fluid dynamics of flight control by kinematic phase lag variation between two robotic insect wings

The fluid dynamics of flight control by kinematic phase lag variation between two robotic insect wings

Experimental Structural Dynamic Characterization of the Hawkmoth (Manduca Sexta) Forewing

Dragonfly flight: free-flight and tethered flow visualizations reveal a diverse array of unsteady lift-generating mechanisms, controlled primarilyviaangle of attack

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