Richard Bomphrey

Application of digital particle image velocimetry to insect aerodynamics: Measurement of the leading-edge vortex and near wake of a Hawkmoth

Publisher: Springer Science and Business Media LLC

Date: 11-01-2006

DOI: 10.1007/S00348-005-0094-5

The aerodynamics ofManduca sexta: digital particle image velocimetry analysis of the leading-edge vortex

Publisher: The Company of Biologists

Date: 15-03-2005

DOI: 10.1242/JEB.01471

Abstract: Here we present the first digital particle image velocimetry (DPIV)analysis of the flow field around the wings of an insect (the tobacco hawkmoth Manduca sexta, tethered to a 6-component force-moment balance in a wind tunnel). A leading-edge vortex (LEV) is present above the wings towards the end of the downstroke, as the net upward force peaks. Our DPIV analyses and smoke visualisations match the results of previous flow visualisation experiments at midwing, and we extend the experiments to provide the first analysis of the flow field above the thorax. Detailed DPIV measurements show that towards the end of the downstroke, the LEV structure is consistent with that recently reported in free-flying butterflies and dragonflies: the LEV is continuous across the thorax and runs along each wing to the wingtip, where it inflects to form the wingtip trailing vortices. The LEV core is 2-3 mm in diameter (approximately 10% of local wing chord) both at the midwing position and over the centreline at 1.2 m s-1 and at 3.5 m s-1flight speeds. At 1.2 m s-1 the measured LEV circulation is 0.012±0.001 m2 s-1 (mean ± s.d.) at the centreline and 0.011±0.001 m2 s-1 halfway along the wing. At 3.5 m s-1LEV circulation is 0.011±0.001 m2 s-1 at the centreline and 0.020±0.004 m2 s-1 at midwing. The DPIV measurements suggest that if there is any spanwise flow in the LEV towards the end of the downstroke its velocity is less than 1 m s-1. Estimates of force production show that the LEV contributes significantly to supporting body weight during bouts of flight at both speeds(more than 10% of body weight at 1.2 m s-1 and 35-65% of body weight at 3.5 m s-1).

Digital particle image velocimetry measurements of the downwash distribution of a desert locust Schistocerca gregaria

Publisher: The Royal Society

Date: 03-11-2006

DOI: 10.1098/RSIF.2005.0090

Abstract: Actuator disc models of insect flight are concerned solely with the rate of momentum transfer to the air that passes through the disc. These simple models assume that an even pressure is applied across the disc, resulting in a uniform downwash distribution. However, a correction factor, k , is often included to correct for the difference in efficiency between the assumed even downwash distribution, and the real downwash distribution. In the absence of any empirical measurements of the downwash distribution behind a real insect, the values of k used in the literature have been necessarily speculative. Direct measurement of this efficiency factor is now possible, and could be used to compare the relative efficiencies of insect flight across the Class. Here, we use Digital Particle Image Velocimetry to measure the instantaneous downwash distribution, mid-downstroke, of a tethered desert locust ( Schistocerca gregaria ). By integrating the downwash distribution, we are thereby able to provide the first direct empirical measurement of k for an insect. The measured value of k =1.12 corresponds reasonably well with that predicted by previous theoretical studies.

Complete neuroanatomy of dragonfly wings suggests direct sensing of aeroelastic deformations

Publisher: Cold Spring Harbor Laboratory

Date: 11-04-2021

DOI: 10.1101/2021.04.11.439336

Abstract: Can mechanosensors in animal wings allow reconstruction of the wing aeroelastic states? Little is known about how flying animals utilize wing mechanosensation to monitor the dynamic state of their highly deformable wings. Odonata, dragonflies and damselflies, are a basal lineage of flying insects with excellent flight performance, and their wing mechanics have been studied extensively. Here, we present a comprehensive map of the wing sensory system for two Odonata species, including both the external sensor morphologies and internal neuroanatomy. We identified eight morphological classes of sensors most were mechanosensors innervated by a single neuron. Their innervation patterns and morphologies minimize axon length and allow morphological latency compensation. We further mapped the major veins of another 13 Odonata species across 10 families and identified consistent sensor distribution patterns, with sensor count scaling with wing length. Finally, we constructed a high-fidelity finite element model of a dragonfly wing for structural analysis. Our dynamic loading simulations revealed features of the strain fields that wing sensor arrays could detect to encode different wing deformation states. Taken together, this work marks the first step toward an integrated understanding of fly-by-feel control in animal flight.

Royal Veterinary College

Location: United Kingdom of Great Britain and Northern Ireland

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Discovery Projects - Grant ID: DP130103850

Start Date: 2013

End Date: 08-2016

Amount: $380,000.00

Funder: Australian Research Council