Soaring Birds as “Maxwell Demons”

  • Ferdinand Hendriks


The suggestion implied in the title of this theoretical article was made by Samuel Langley (1893) in his treatise “The Internal Work of the Wind”. He, like a number of other scientists of his time, during which there was great curiosity about bird flight and, as a consequence, about the nature of the wind, was particularly fascinated by the question if birds might in some sense rectify the turbulent fluctuations of the wind as a means to offset their drag, and thereby stay aloft. Until it was discovered by Idrac (1931) that thermal updraughts must in most cases be considered the true source of energy in soaring, there was lively debate over the ways in which turbulence might be exploitable in flight. The work of Klemperer (1926) and Breguet (1925) is typical in this respect.


Aerodynamic Force Turbulent Fluctuation Inertial Subrange Lively Debate Black Kite 
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Copyright information

© Springer Science+Business Media New York 1975

Authors and Affiliations

  • Ferdinand Hendriks
    • 1
  1. 1.IBM Thomas J. Watson Research CenterYorktown HeightsUSA

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