A quantitative comparison of bird and bat wakes.
Johansson, Christoffer LU
; Wolf, Marta
LU
and Hedenström, Anders
LU
(2010)
In Journal of the Royal Society Interface
7.
p.61-66
- Abstract
- Qualitative comparison of bird and bat wakes has demonstrated significant differences in the structure of the far wake. Birds have been found to have a unified vortex wake of the two wings, while bats have a more complex wake with gradients in the circulation along the wingspan, and with each wing generating its own vortex structure. Here, we compare quantitative measures of the circulation in the far wake of three bird and one bat species. We find that bats have a significantly stronger normalized circulation of the start vortex than birds. We also find differences in how the circulation develops during the wingbeat as demonstrated by the ratio of the circulation of the dominant start vortex and the total circulation of the same sense.... (More)
- Qualitative comparison of bird and bat wakes has demonstrated significant differences in the structure of the far wake. Birds have been found to have a unified vortex wake of the two wings, while bats have a more complex wake with gradients in the circulation along the wingspan, and with each wing generating its own vortex structure. Here, we compare quantitative measures of the circulation in the far wake of three bird and one bat species. We find that bats have a significantly stronger normalized circulation of the start vortex than birds. We also find differences in how the circulation develops during the wingbeat as demonstrated by the ratio of the circulation of the dominant start vortex and the total circulation of the same sense. Birds show a more prominent change with changing flight speed and a relatively weaker start vortex at minimum power speed than bats. We also find that bats have a higher normalized wake loading based on the start vortex, indicating higher relative induced drag and therefore less efficient lift generation than birds. Our results thus indicate fundamental differences in the aerodynamics of bird and bat flight that will further our understanding of the evolution of vertebrate flight. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1367446
- author
- Johansson, Christoffer
LU
; Wolf, Marta
LU
and Hedenström, Anders
LU
- organization
- publishing date
- 2010
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of the Royal Society Interface
- volume
- 7
- pages
- 61 - 66
- publisher
- The Royal Society of Canada
- external identifiers
-
- wos:000271951100005
- scopus:70349666906
- pmid:19324669
- ISSN
- 1742-5662
- DOI
- 10.1098/rsif.2008.0541
- language
- English
- LU publication?
- yes
- id
- 79996815-3aca-4c5b-b8fe-d9a33b087ecc (old id 1367446)
- date added to LUP
- 2016-04-01 10:13:24
- date last changed
- 2024-10-06 23:29:58
@article{79996815-3aca-4c5b-b8fe-d9a33b087ecc,
abstract = {{Qualitative comparison of bird and bat wakes has demonstrated significant differences in the structure of the far wake. Birds have been found to have a unified vortex wake of the two wings, while bats have a more complex wake with gradients in the circulation along the wingspan, and with each wing generating its own vortex structure. Here, we compare quantitative measures of the circulation in the far wake of three bird and one bat species. We find that bats have a significantly stronger normalized circulation of the start vortex than birds. We also find differences in how the circulation develops during the wingbeat as demonstrated by the ratio of the circulation of the dominant start vortex and the total circulation of the same sense. Birds show a more prominent change with changing flight speed and a relatively weaker start vortex at minimum power speed than bats. We also find that bats have a higher normalized wake loading based on the start vortex, indicating higher relative induced drag and therefore less efficient lift generation than birds. Our results thus indicate fundamental differences in the aerodynamics of bird and bat flight that will further our understanding of the evolution of vertebrate flight.}},
author = {{Johansson, Christoffer and Wolf, Marta and Hedenström, Anders}},
issn = {{1742-5662}},
language = {{eng}},
pages = {{61--66}},
publisher = {{The Royal Society of Canada}},
series = {{Journal of the Royal Society Interface}},
title = {{A quantitative comparison of bird and bat wakes.}},
url = {{http://dx.doi.org/10.1098/rsif.2008.0541}},
doi = {{10.1098/rsif.2008.0541}},
volume = {{7}},
year = {{2010}},
}