Wake structure and wingbeat kinematics of a house-martin Delichon urbica
(2007) In Journal of the Royal Society Interface 4(15). p.659-668- Abstract
- The wingbeat kinematics and wake structure of a trained house martin in free, steady flight in a wind tunnel have been studied over a range of flight speeds, and compared and contrasted with similar measurements for a thrush nightingale and a pair of robins. The house martin has a higher aspect ratio (more slender) wing, and is a more obviously agile and aerobatic flyer, catching insects on the wing. The wingbeat is notable for the presence at higher flight speeds of a characteristic pause in the upstroke. The essential characteristics of the wing motions can be reconstructed with a simple two-frequency model derived from Fourier analysis. At slow speeds, the distribution of wake vorticity is more simple than for the other previously... (More)
- The wingbeat kinematics and wake structure of a trained house martin in free, steady flight in a wind tunnel have been studied over a range of flight speeds, and compared and contrasted with similar measurements for a thrush nightingale and a pair of robins. The house martin has a higher aspect ratio (more slender) wing, and is a more obviously agile and aerobatic flyer, catching insects on the wing. The wingbeat is notable for the presence at higher flight speeds of a characteristic pause in the upstroke. The essential characteristics of the wing motions can be reconstructed with a simple two-frequency model derived from Fourier analysis. At slow speeds, the distribution of wake vorticity is more simple than for the other previously measured birds, and the upstroke does not contribute to weight support. The upstroke becomes gradually more significant as the flight speed increases, and although the vortex wake shows a signature of the pause phase, the global circulation measurements are otherwise in good agreement with surprisingly simple aerodynamic models, and with predictions across the different species, implying quite similar aerodynamic performance of the wing sections. The local Reynolds numbers of the wing sections are sufficiently low that the well-known instabilities of attached laminar flows over lifting surfaces, which are known to occur at two to three times this value, may not develop. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/691835
- author
- Rosén, Mikael LU ; Spedding, G. R. and Hedenström, Anders LU
- organization
- publishing date
- 2007
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Delichon urbica, image velocimetry, digital particle, wind tunnel, vortex wakes, bird flight, aerodynamics
- in
- Journal of the Royal Society Interface
- volume
- 4
- issue
- 15
- pages
- 659 - 668
- publisher
- The Royal Society of Canada
- external identifiers
-
- wos:000247907100007
- scopus:34547624350
- ISSN
- 1742-5662
- DOI
- 10.1098/rsif.2007.0215
- language
- English
- LU publication?
- yes
- id
- e9ca4826-6af4-44f7-95be-211203732084 (old id 691835)
- date added to LUP
- 2016-04-01 11:38:51
- date last changed
- 2022-01-26 08:05:38
@article{e9ca4826-6af4-44f7-95be-211203732084,
abstract = {{The wingbeat kinematics and wake structure of a trained house martin in free, steady flight in a wind tunnel have been studied over a range of flight speeds, and compared and contrasted with similar measurements for a thrush nightingale and a pair of robins. The house martin has a higher aspect ratio (more slender) wing, and is a more obviously agile and aerobatic flyer, catching insects on the wing. The wingbeat is notable for the presence at higher flight speeds of a characteristic pause in the upstroke. The essential characteristics of the wing motions can be reconstructed with a simple two-frequency model derived from Fourier analysis. At slow speeds, the distribution of wake vorticity is more simple than for the other previously measured birds, and the upstroke does not contribute to weight support. The upstroke becomes gradually more significant as the flight speed increases, and although the vortex wake shows a signature of the pause phase, the global circulation measurements are otherwise in good agreement with surprisingly simple aerodynamic models, and with predictions across the different species, implying quite similar aerodynamic performance of the wing sections. The local Reynolds numbers of the wing sections are sufficiently low that the well-known instabilities of attached laminar flows over lifting surfaces, which are known to occur at two to three times this value, may not develop.}},
author = {{Rosén, Mikael and Spedding, G. R. and Hedenström, Anders}},
issn = {{1742-5662}},
keywords = {{Delichon urbica; image velocimetry; digital particle; wind tunnel; vortex wakes; bird flight; aerodynamics}},
language = {{eng}},
number = {{15}},
pages = {{659--668}},
publisher = {{The Royal Society of Canada}},
series = {{Journal of the Royal Society Interface}},
title = {{Wake structure and wingbeat kinematics of a house-martin Delichon urbica}},
url = {{http://dx.doi.org/10.1098/rsif.2007.0215}},
doi = {{10.1098/rsif.2007.0215}},
volume = {{4}},
year = {{2007}},
}