Leading-edge vortex improves lift in slow-flying bats

Science

Volumn 319, Issue 5867, 2008, Pages 1250-1253

  Muijres, F T ^a   Johansson, L C ^a   Barfield, R ^a   Wolf, M ^a   Spedding, G R ^b   Hedenstrom A ^a  

^a LUND UNIVERSITY   (Sweden)

^b University of Southern California ^*  (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AERODYNAMICS; BAT; FLIGHT; FLY; IMAGE; NECTAR;

ARTICLE; BAT; FLYING; KINEMATICS; NONHUMAN; PARTICLE IMAGE VELOCIMETRY; PRIORITY JOURNAL; ROTATION; STEADY STATE; VORTEX MOTION;

AIR MOVEMENTS; ANIMALS; BIOMECHANICS; CHIROPTERA; FLIGHT, ANIMAL; MOVEMENT; RHEOLOGY; WING;

ANIMALIA; HEXAPODA; VERTEBRATA;

EID: 40049091461     PISSN: 00368075     EISSN: 10959203     Source Type: Journal    
DOI: 10.1126/science.1153019     Document Type: Article

References (33)

1. F.-O. Lehmann, Naturwissenschaften 91, 101 (2004).
2. Quasi-steady-state wing theory assumes that the forces on a moving wing are equivalent to the sum of the forces on a fixed wing over a sequence of attitudes that track the wing motion. This model neglects acceleration forces and unsteady aerodynamic effects.
3. M. H. Dickinson, F.-O. Lehmann, S. P. Sane, Science 284, 1954 (1999).
4. T. Weis-Fogh, J. Exp. Biol. 59, 169 (1973).
5. T. Maxworthy, J. Fluid Mech. 93, 47 (1979).
6. R. B. Srygley, A. L. R. Thomas, Nature 420, 660 (2002).
7. C. Ellington, Philos. Trans. R. Soc. London Ser. B 305, 1 (1984).
8. S. Vogel, Life in Moving Fluids (Princeton Univ. Press, Princeton, NJ, 1994).
9. C. P. Ellington, C. van den Berg, A. P. Willmott, A. L. R. Thomas, Nature 384, 626 (1996).
10. T. Maxworthy, J. Fluid Mech. 587, 471 (2007).
11. M. W. Luttges, in Frontiers in Experimental Fluid Mechanics, M. Gad-El-Hak, Ed. (Springer, Berlin, 1989), pp. 429-456.
12. A. L. R. Thomas, G. K. Taylor, R. B. Srygley, R. L. Nudds, R. J. Bomphrey, J. Exp. Biol. 207, 4299 (2004).
13. C. van den Berg, C. P. Ellington, Philos. Trans. R. Soc. London Ser. B 352, 329 (1997).
14. R. J. Bomphrey, N. J. Lawson, N. J. Harding, G. K. Taylor, A. L. R. Thomas, J. Exp. Biol. 208, 1079 (2005).
15. M. H. Dickinson, K. G. Gotz, J. Exp. Biol. 174, 45 (1993).
16. A. Willmott, C. Ellington, J. Exp. Biol. 200, 2693 (1997).
17. C. Somps, M. Luttges, Science 228, 1326 (1985).
18. U. M. Norberg, in Swimming and Flying in Nature, vol. 2, T. Y.-T. Wu, C. J. Brokaw, C. Brennen, Eds. (Plenum, New York, 1975), pp. 869-881.
19. A. Hedenström et al., Science 316, 894 (2007).
20. D. R. Warrick, B. W. Tobalske, D. R. Powers, Nature 435, 1094 (2005).
21. J. J. Videler, E. J. Stamhuis, G. D. E. Povel, Science 306, 1960 (2004).
22. See supporting material on Science Online.
23. 5) where the aerodynamics are notoriously hard to predict and control.
24. St = fA/U∞ (f is wingbeat frequency and A is the tip-to-tip vertical excursion of the wing tip). St is proportional to the ratio of the average wingbeat velocity to the steady forward speed and is an indication of the unsteadiness and efficiency of vortex generation.
25. For an incompressible fluid, the divergence in a planar velocity field is related to the change in out-of-plane flow velocity. When the divergence is positive, the fluid works as a fluid source in the planar velocity field, decreasing the out-of-plane velocity. When it is negative, it is a fluid sink, which increases the out-of-plane velocity.
26. E. V. Laitone, Exp. Fluids 23, 405 (1997).
27. J. M. Birch, M. H. Dickinson, Nature 412, 729 (2001).
28. J. M. Birch, W. B. Dickson, M. H. Dickinson, J. Exp. Biol. 207, 1063 (2004).
29. J. D. Anderson, Fundamentals of Aerodynamics (McGraw-Hill, Singapore, 1991).
30. R. Bomphrey, N. Lawson, G. Taylor, A. Thomas, Exp. Fluids 40, 546 (2006).
31. D. A. Read, F. S. Hover, M. S. Triantafyllou, J. Fluids Struct. 17, 163 (2003).
32. S. M. Swartz, M. S. Groves, H. D. Kim, W. R. Walsh, J. Zool. 239, 357 (1996).
33. We thank R. von Busse and Y. Winter for their support. This work was supported by grants from the Swedish Research Council, the Swedish Foundation for International Cooperation in Research and Higher Education, the Knut and Alice Wallenberg Foundation, the Crafoord Foundation, the Magnus Bergvall Foundation, and the Royal Physiographical Society.