Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 29 February 2008:
Vol. 319. no. 5867, pp. 1250 - 1253
DOI: 10.1126/science.1153019
Prev | Table of Contents | Next

Reports

Leading-Edge Vortex Improves Lift in Slow-Flying Bats

F. T. Muijres,1 L. C. Johansson,1 R. Barfield,1 M. Wolf,1 G. R. Spedding,2 A. Hedenström1*

Staying aloft when hovering and flying slowly is demanding. According to quasi–steady-state aerodynamic theory, slow-flying vertebrates should not be able to generate enough lift to remain aloft. Therefore, unsteady aerodynamic mechanisms to enhance lift production have been proposed. Using digital particle image velocimetry, we showed that a small nectar-feeding bat is able to increase lift by as much as 40% using attached leading-edge vortices (LEVs) during slow forward flight, resulting in a maximum lift coefficient of 4.8. The airflow passing over the LEV reattaches behind the LEV smoothly to the wing, despite the exceptionally large local angles of attack and wing camber. Our results show that the use of unsteady aerodynamic mechanisms in flapping flight is not limited to insects but is also used by larger and heavier animals.

1 Department of Theoretical Ecology, Lund University, SE-223 62 Lund, Sweden.
2 Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089–1191, USA.

* To whom correspondence should be addressed. E-mail: anders.hedenstrom{at}teorekol.lu.se

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Aeroecology: probing and modeling the aerosphere.
T. H. Kunz, S. A. Gauthreaux Jr, N. I. Hristov, J. W. Horn, G. Jones, E. K. V. Kalko, R. P. Larkin, G. F. McCracken, S. M. Swartz, R. B. Srygley, et al. (2008)
Integr. Comp. Biol. 48, 1-11
   Abstract »    Full Text »    PDF »


ADVERTISEMENT
Click Me!

ADVERTISEMENT
Click Me!

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)