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Quantitative studies of the wakes of freely flying birds in a low-turbulence wind tunnel

Spedding, GR; Hedenström, Anders LU and Rosén, Mikael LU (2003) In Experiments in Fluids 34(2). p.291-303
Abstract
A novel application of DPIV methods is presented for measuring velocity and vorticity distributions in vertical cross sections through the wake of a freely flying bird (thrush nightingale) in a wind tunnel. A dual-camera system is used, and successive cross-correlation operations remove lens/camera distortions, and then the undisturbed background flow, so that the final operation simply examines the disturbance effect of the bird alone. The concentration and tuning of processing methods to the disturbance quantities allows full exploitation of the correlation calculation and estimation algorithms. Since the ultimate objective is to deduce forces and power requirements on the bird itself from the wake structure, the analytical procedure is... (More)
A novel application of DPIV methods is presented for measuring velocity and vorticity distributions in vertical cross sections through the wake of a freely flying bird (thrush nightingale) in a wind tunnel. A dual-camera system is used, and successive cross-correlation operations remove lens/camera distortions, and then the undisturbed background flow, so that the final operation simply examines the disturbance effect of the bird alone. The concentration and tuning of processing methods to the disturbance quantities allows full exploitation of the correlation calculation and estimation algorithms. Since the ultimate objective is to deduce forces and power requirements on the bird itself from the wake structure, the analytical procedure is followed through an example on a fixed airfoil, before sample results from extensive bird flight tests are described. The wake structure of the thrush nightingale in slow (5-m/s) flight is qualitatively quite similar to those previously described in the literature, but certain quantitative details are different in important respects. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Experiments in Fluids
volume
34
issue
2
pages
291 - 303
publisher
Springer
external identifiers
  • wos:000181540600013
  • scopus:0037297190
ISSN
1432-1114
DOI
language
English
LU publication?
yes
id
b28510df-7b1c-46a1-a8e3-9b284877a9d8 (old id 135496)
date added to LUP
2007-06-25 12:50:01
date last changed
2018-05-29 09:46:10
@article{b28510df-7b1c-46a1-a8e3-9b284877a9d8,
  abstract     = {A novel application of DPIV methods is presented for measuring velocity and vorticity distributions in vertical cross sections through the wake of a freely flying bird (thrush nightingale) in a wind tunnel. A dual-camera system is used, and successive cross-correlation operations remove lens/camera distortions, and then the undisturbed background flow, so that the final operation simply examines the disturbance effect of the bird alone. The concentration and tuning of processing methods to the disturbance quantities allows full exploitation of the correlation calculation and estimation algorithms. Since the ultimate objective is to deduce forces and power requirements on the bird itself from the wake structure, the analytical procedure is followed through an example on a fixed airfoil, before sample results from extensive bird flight tests are described. The wake structure of the thrush nightingale in slow (5-m/s) flight is qualitatively quite similar to those previously described in the literature, but certain quantitative details are different in important respects.},
  author       = {Spedding, GR and Hedenström, Anders and Rosén, Mikael},
  issn         = {1432-1114},
  language     = {eng},
  number       = {2},
  pages        = {291--303},
  publisher    = {Springer},
  series       = {Experiments in Fluids},
  title        = {Quantitative studies of the wakes of freely flying birds in a low-turbulence wind tunnel},
  url          = {http://dx.doi.org/},
  volume       = {34},
  year         = {2003},
}