Hovering performance of Anna's hummingbirds (Calypte anna) in ground effect
(2014) In Journal of the Royal Society Interface 11(98).- Abstract
- Aerodynamic performance and energetic savings for flight in ground effect are theoretically maximized during hovering, but have never been directly measured for flying animals. We evaluated flight kinematics, metabolic rates and induced flow velocities for Anna's hummingbirds hovering at heights (relative to wing length R 5.5 cm) of 0.7R, 0.9R, 1.1R, 1.7R, 2.2R and 8R above a solid surface. Flight at heights less than or equal to 1.1R resulted in significant reductions in the body angle, tail angle, anatomical stroke plane angle, wake-induced velocity, and mechanical and metabolic power expenditures when compared with flight at the control height of 8R. By contrast, stroke plane angle relative to horizontal, wingbeat amplitude and wingbeat... (More)
- Aerodynamic performance and energetic savings for flight in ground effect are theoretically maximized during hovering, but have never been directly measured for flying animals. We evaluated flight kinematics, metabolic rates and induced flow velocities for Anna's hummingbirds hovering at heights (relative to wing length R 5.5 cm) of 0.7R, 0.9R, 1.1R, 1.7R, 2.2R and 8R above a solid surface. Flight at heights less than or equal to 1.1R resulted in significant reductions in the body angle, tail angle, anatomical stroke plane angle, wake-induced velocity, and mechanical and metabolic power expenditures when compared with flight at the control height of 8R. By contrast, stroke plane angle relative to horizontal, wingbeat amplitude and wingbeat frequency were unexpectedly independent of height from ground. Qualitative smoke visualizations suggest that each wing generates a vortex ring during both down-and upstroke. These rings expand upon reaching the ground and present a complex turbulent interaction below the bird's body. Nonetheless, hovering near surfaces results in substantial energetic benefits for hummingbirds, and by inference for all volant taxa that either feed at flowers or otherwise fly close to plant or other surfaces. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4602578
- author
- Kim, Erica J. ; Wolf, Marta LU ; Ortega-Jimenez, Victor Manuel ; Cheng, Stanley H. and Dudley, Robert
- organization
- publishing date
- 2014
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- ground effect, hovering, induced velocity, metabolic power, vortex wake
- in
- Journal of the Royal Society Interface
- volume
- 11
- issue
- 98
- article number
- 20140505
- publisher
- The Royal Society of Canada
- external identifiers
-
- pmid:24990291
- wos:000338519300014
- scopus:84905053621
- pmid:24990291
- ISSN
- 1742-5662
- DOI
- 10.1098/rsif.2014.0505
- language
- English
- LU publication?
- yes
- id
- c7ad00ee-77ea-4ca0-a297-53d96fb11653 (old id 4602578)
- date added to LUP
- 2016-04-01 10:25:56
- date last changed
- 2022-01-25 23:09:23
@article{c7ad00ee-77ea-4ca0-a297-53d96fb11653,
abstract = {{Aerodynamic performance and energetic savings for flight in ground effect are theoretically maximized during hovering, but have never been directly measured for flying animals. We evaluated flight kinematics, metabolic rates and induced flow velocities for Anna's hummingbirds hovering at heights (relative to wing length R 5.5 cm) of 0.7R, 0.9R, 1.1R, 1.7R, 2.2R and 8R above a solid surface. Flight at heights less than or equal to 1.1R resulted in significant reductions in the body angle, tail angle, anatomical stroke plane angle, wake-induced velocity, and mechanical and metabolic power expenditures when compared with flight at the control height of 8R. By contrast, stroke plane angle relative to horizontal, wingbeat amplitude and wingbeat frequency were unexpectedly independent of height from ground. Qualitative smoke visualizations suggest that each wing generates a vortex ring during both down-and upstroke. These rings expand upon reaching the ground and present a complex turbulent interaction below the bird's body. Nonetheless, hovering near surfaces results in substantial energetic benefits for hummingbirds, and by inference for all volant taxa that either feed at flowers or otherwise fly close to plant or other surfaces.}},
author = {{Kim, Erica J. and Wolf, Marta and Ortega-Jimenez, Victor Manuel and Cheng, Stanley H. and Dudley, Robert}},
issn = {{1742-5662}},
keywords = {{ground effect; hovering; induced velocity; metabolic power; vortex wake}},
language = {{eng}},
number = {{98}},
publisher = {{The Royal Society of Canada}},
series = {{Journal of the Royal Society Interface}},
title = {{Hovering performance of Anna's hummingbirds (Calypte anna) in ground effect}},
url = {{http://dx.doi.org/10.1098/rsif.2014.0505}},
doi = {{10.1098/rsif.2014.0505}},
volume = {{11}},
year = {{2014}},
}