Quantitative studies of the wakes of freely flying birds in a low-turbulence wind tunnel
Author
Summary, in English
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.
Publishing year
2003
Language
English
Pages
291-303
Publication/Series
Experiments in Fluids
Volume
34
Issue
2
Document type
Journal article
Publisher
Springer
Topic
- Biological Sciences
Status
Published
Research group
- Animal Flight Lab
ISBN/ISSN/Other
- ISSN: 1432-1114