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A note on the propulsive systems of fishes and birds, with possible application to manpowered flight

Published online by Cambridge University Press:  04 July 2016

J. S. Elliott
J. S. Elliott*
Affiliation:
Aerodynamics Department, RAE, Farnborough
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Extract

It has long been pointed out by Gray that large aquatic animals, notably the dolphin, have been observed to achieve speeds which appear to be far beyond their muscular capabilities, unless they somehow experience laminar flow. Many workers have puzzled over this problem, and various possibilities have been propounded. In particular Wu has carried out a long theoretical analysis of the swimming of a slender fish in two dimensions, and he mentions the prospect of the zero momentum wake.

The principle of the zero momentum wake (or boundary layer propulsion, as it is sometimes called) has often attracted the attention of aircraft propulsion engineers. A small wind tunnel experiment by Göbel and Oehler is of interest. They took a circular sieve, representing profile drag, and set this in relation to a propeller of the same diameter as the sieve. The sieve and the propeller were set side-by-side on a bar, and the power required to propel the model was measured. Then the sieve and the propeller were set in tandem, with the sieve in front of the propeller, and the power required measured again. The power required for the tandem arrangement was found to be significantly less than that required for the side-by-side arrangement.

Type
Research Article
Information
The Aeronautical Journal , Volume 88 , Issue 877 , February 2001 , pp. 296 - 298
Copyright
Copyright © Royal Aeronautical Society 1984 

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References

1. Wu, T. Y. Hydrodynamics of swimming propulsion, (three parts). Jnl Fluid Mech. 1971, 46 part 2, 337–355 and 46 part 3, 521-568.Google Scholar
2. Göbel, D. and Oehler, C. Untersuchungen über die Besch-leunigung von Nachlaufströmungen für Vortriebszwecke. Z. Flugwiss. 1964. 12 Heft 11.Google Scholar
3. Manheimer-Timnat, Y. and Thring, M. W. A note on boundary layer propulsion. Israel Jnl of Technology, 1973, 11, 4, 291–298.Google Scholar
4. Pennycuick, C. J. Animal Flight, Edward Arnold, 1972.Google Scholar
5. Gray, J. Animal Locomotion, Weidenfeld and Nicolson, 1968.Google Scholar
6. Pringle, J. W. S. Insect Flight, Cambridge University Press, 1957.Google Scholar
7. Kelly, H. R. and Bowlus, G. H. Swimming hinged hydrofoils, NAVWEPS Report 8411, NOTS TP 3342, 1963.Google Scholar
8. Wu, T. Y. Swimming of a waving plate, Jnl Fluid Mech. May 1961,10, 321–344.Google Scholar
9. Hertel, H. Gekoppelte Biege- und Drehschwingungen als Antrieb, VDI-Z, September (II), 1967, 109, 26.Google Scholar
10. Townend, H. C. H. Note on the possibility of flight by human power, Jnl Royal Aero Society, 1937, 41, 609.Google Scholar
11. Burnell, R. D. Sculling, Oxford University Press, 1955.Google Scholar