Structure of the vortex wake in hovering Anna's hummingbirds (Calypte anna).
(2013) In Proceedings of the Royal Society B: Biological Sciences 280(1773). p.2-20132391- Abstract
- Hummingbirds are specialized hoverers for which the vortex wake has been described as a series of single vortex rings shed primarily during the downstroke. Recent findings in bats and birds, as well as in a recent study on Anna's hummingbirds, suggest that each wing may shed a discrete vortex ring, yielding a bilaterally paired wake. Here, we describe the presence of two discrete rings in the wake of hovering Anna's hummingbirds, and also infer force production through a wingbeat with contributions to weight support. Using flow visualization, we found separate vortices at the tip and root of each wing, with 15% stronger circulation at the wingtip than at the root during the downstroke. The upstroke wake is more complex, with... (More)
- Hummingbirds are specialized hoverers for which the vortex wake has been described as a series of single vortex rings shed primarily during the downstroke. Recent findings in bats and birds, as well as in a recent study on Anna's hummingbirds, suggest that each wing may shed a discrete vortex ring, yielding a bilaterally paired wake. Here, we describe the presence of two discrete rings in the wake of hovering Anna's hummingbirds, and also infer force production through a wingbeat with contributions to weight support. Using flow visualization, we found separate vortices at the tip and root of each wing, with 15% stronger circulation at the wingtip than at the root during the downstroke. The upstroke wake is more complex, with near-continuous shedding of vorticity, and circulation of approximately equal magnitude at tip and root. Force estimates suggest that the downstroke contributes 66% of required weight support, whereas the upstroke generates 35%. We also identified a secondary vortex structure yielding 8-26% of weight support. Lift production in Anna's hummingbirds is more evenly distributed between the stroke phases than previously estimated for Rufous hummingbirds, in accordance with the generally symmetric down- and upstrokes that characterize hovering in these birds. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4179975
- author
- Wolf, Marta LU ; Ortega-Jimenez, Victor Manuel and Dudley, Robert
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- aerodynamics, flight, hovering, hummingbird, lift, vortex wake
- in
- Proceedings of the Royal Society B: Biological Sciences
- volume
- 280
- issue
- 1773
- pages
- 2 - 20132391
- publisher
- Royal Society Publishing
- external identifiers
-
- pmid:24174113
- wos:000330325600020
- scopus:84887002530
- ISSN
- 1471-2954
- DOI
- 10.1098/rspb.2013.2391
- language
- English
- LU publication?
- yes
- id
- 86455bb2-11c4-4a8d-85d2-c8c55afe322e (old id 4179975)
- date added to LUP
- 2016-04-01 15:04:00
- date last changed
- 2022-04-14 21:08:16
@article{86455bb2-11c4-4a8d-85d2-c8c55afe322e,
abstract = {{Hummingbirds are specialized hoverers for which the vortex wake has been described as a series of single vortex rings shed primarily during the downstroke. Recent findings in bats and birds, as well as in a recent study on Anna's hummingbirds, suggest that each wing may shed a discrete vortex ring, yielding a bilaterally paired wake. Here, we describe the presence of two discrete rings in the wake of hovering Anna's hummingbirds, and also infer force production through a wingbeat with contributions to weight support. Using flow visualization, we found separate vortices at the tip and root of each wing, with 15% stronger circulation at the wingtip than at the root during the downstroke. The upstroke wake is more complex, with near-continuous shedding of vorticity, and circulation of approximately equal magnitude at tip and root. Force estimates suggest that the downstroke contributes 66% of required weight support, whereas the upstroke generates 35%. We also identified a secondary vortex structure yielding 8-26% of weight support. Lift production in Anna's hummingbirds is more evenly distributed between the stroke phases than previously estimated for Rufous hummingbirds, in accordance with the generally symmetric down- and upstrokes that characterize hovering in these birds.}},
author = {{Wolf, Marta and Ortega-Jimenez, Victor Manuel and Dudley, Robert}},
issn = {{1471-2954}},
keywords = {{aerodynamics; flight; hovering; hummingbird; lift; vortex wake}},
language = {{eng}},
number = {{1773}},
pages = {{2--20132391}},
publisher = {{Royal Society Publishing}},
series = {{Proceedings of the Royal Society B: Biological Sciences}},
title = {{Structure of the vortex wake in hovering Anna's hummingbirds (Calypte anna).}},
url = {{http://dx.doi.org/10.1098/rspb.2013.2391}},
doi = {{10.1098/rspb.2013.2391}},
volume = {{280}},
year = {{2013}},
}