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Vortex wakes of birds: recent developments using digital particle image velocimetry in a wind tunnel

Författare:
Publiceringsår: 2006
Språk: Engelska
Sidor: 535-549
Publikation/Tidskrift/Serie: Animal Biology
Volym: 56
Nummer: 4
Dokumenttyp: Artikel
Förlag: Brill

Sammanfattning

A flying animal generates a trail of wake vortices that contain information about the time history and magnitude of aerodynamic forces developed on the wings and body. Methods for visualising and recording wake vortices have been developed, allowing quantitative measurements by digital particle image velocimetry (DPIV). Results from DPIV experiments in a wind tunnel are presented for four passerine species of differing size and morphology. The normalised vorticity and its integrated quantity, circulation (Gamma) both decline gradually with increasing flight speed. The measured circulations are successfully explained by a simple aerodynamic model where a normalised circulation, Gamma/Uc, represents half the time-averaged lift coefficient, which is > 2 at 4 m s(-1) for a thrush nightingale.

Disputation

Nyckelord

  • Biology and Life Sciences
  • added mass
  • bird flight
  • digital particle image
  • velocimetry
  • DPIV
  • vortex wakes
  • aerodynamics

Övriga

Published
Yes
  • ISSN: 1570-7555
  • ISSN: 1570-7563

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