The near and far wake of Pallas' long tongued bat (Glossophaga soricina).
(2008) In Journal of Experimental Biology 211(Pt 18). p.2909-2918- Abstract
- The wake structures of a bat in flight have a number of characteristics not associated with any of the bird species studied to this point. Unique features include discrete vortex rings generating negative lift at the end of the upstroke at medium and high speeds, each wing generating its own vortex loop, and a systematic variation in the circulation of the start and stop vortices along the wingspan, with increasing strength towards the wing tips. Here we analyse in further detail some previously published data from quantitative measurements of the wake behind a small bat species flying at speeds ranging from 1.5 to 7 m s(-1) in a wind tunnel. The data are extended to include both near- and far-wake measurements. The near-/far-wake... (More)
- The wake structures of a bat in flight have a number of characteristics not associated with any of the bird species studied to this point. Unique features include discrete vortex rings generating negative lift at the end of the upstroke at medium and high speeds, each wing generating its own vortex loop, and a systematic variation in the circulation of the start and stop vortices along the wingspan, with increasing strength towards the wing tips. Here we analyse in further detail some previously published data from quantitative measurements of the wake behind a small bat species flying at speeds ranging from 1.5 to 7 m s(-1) in a wind tunnel. The data are extended to include both near- and far-wake measurements. The near-/far-wake comparisons show that although the measured peak vorticity of the start and stop vortices decreases with increasing downstream distance from the wing, the total circulation remains approximately constant. As the wake evolves, the diffuse stop vortex shed at the inner wing forms a more concentrated vortex in the far wake. Taken together, the results show that studying the far wake, which has been the standard procedure, nevertheless risks missing details of the wake. Although study of the far wake alone can lead to the misinterpretation of the wake topology, the net, overall circulation of the main wake vortices can be preserved so that approximate momentum balance calculations are not unreasonable within the inevitably large experimental uncertainties. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1243312
- author
- Johansson, Christoffer LU ; Wolf, Marta LU ; von Busse, Rhea ; Winter, York ; Spedding, Geoffrey R and Hedenström, Anders LU
- organization
- publishing date
- 2008
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- DPIV, wake, aerodynamics, flight, bats, Glossophaga soricina
- in
- Journal of Experimental Biology
- volume
- 211
- issue
- Pt 18
- pages
- 2909 - 2918
- publisher
- The Company of Biologists Ltd
- external identifiers
-
- wos:000258921700006
- scopus:54349097779
- ISSN
- 1477-9145
- DOI
- 10.1242/jeb.018192
- language
- English
- LU publication?
- yes
- id
- fe29dbfb-888b-40e9-b665-262b52840502 (old id 1243312)
- date added to LUP
- 2016-04-01 11:49:36
- date last changed
- 2022-03-13 01:17:37
@article{fe29dbfb-888b-40e9-b665-262b52840502,
abstract = {{The wake structures of a bat in flight have a number of characteristics not associated with any of the bird species studied to this point. Unique features include discrete vortex rings generating negative lift at the end of the upstroke at medium and high speeds, each wing generating its own vortex loop, and a systematic variation in the circulation of the start and stop vortices along the wingspan, with increasing strength towards the wing tips. Here we analyse in further detail some previously published data from quantitative measurements of the wake behind a small bat species flying at speeds ranging from 1.5 to 7 m s(-1) in a wind tunnel. The data are extended to include both near- and far-wake measurements. The near-/far-wake comparisons show that although the measured peak vorticity of the start and stop vortices decreases with increasing downstream distance from the wing, the total circulation remains approximately constant. As the wake evolves, the diffuse stop vortex shed at the inner wing forms a more concentrated vortex in the far wake. Taken together, the results show that studying the far wake, which has been the standard procedure, nevertheless risks missing details of the wake. Although study of the far wake alone can lead to the misinterpretation of the wake topology, the net, overall circulation of the main wake vortices can be preserved so that approximate momentum balance calculations are not unreasonable within the inevitably large experimental uncertainties.}},
author = {{Johansson, Christoffer and Wolf, Marta and von Busse, Rhea and Winter, York and Spedding, Geoffrey R and Hedenström, Anders}},
issn = {{1477-9145}},
keywords = {{DPIV; wake; aerodynamics; flight; bats; Glossophaga soricina}},
language = {{eng}},
number = {{Pt 18}},
pages = {{2909--2918}},
publisher = {{The Company of Biologists Ltd}},
series = {{Journal of Experimental Biology}},
title = {{The near and far wake of Pallas' long tongued bat (Glossophaga soricina).}},
url = {{http://dx.doi.org/10.1242/jeb.018192}},
doi = {{10.1242/jeb.018192}},
volume = {{211}},
year = {{2008}},
}