Experiments in Fluids

, Volume 51, Issue 2, pp 511–525 | Cite as

Actuator disk model and span efficiency of flapping flight in bats based on time-resolved PIV measurements

  • Florian T. Muijres
  • Geoffrey R. Spedding
  • York Winter
  • Anders Hedenström
Research Article


All animals flap their wings in powered flight to provide both lift and thrust, yet few human-engineered designs do so. When combined with flexible wing surfaces, the resulting unsteady fluid flows and interactions in flapping flight can be complex to describe, understand, and model. Here, a simple modified actuator disk is used in a quasi-steady description of the net aerodynamic lift forces on several species of bat whose wakes are measured with time-resolved PIV. The model appears to capture the time-averaged and instantaneous lift forces on the wings and body, and could be used as basis for comparing flapping flight efficiency of different animal species and micro air vehicle designs.


Flight Speed Vortex Loop Actuator Disk Outer Wing Root Vortex 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We would like to thank Rhea von Busse for her extensive help during the experiments, and Christoffer Johansson for his advice concerning the analysis. The Lavision stereo PIV system was acquired through a generous grant from the Knut and Alice Wallenberg foundation. The research was funded by the Swedish Research Council to A.H. This report received support from the Center for Animal Movement Research (CAnMove) financed by a Linnaeus grant (349-2007-8690) from the Swedish Research Council and Lund University.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Florian T. Muijres
    • 1
  • Geoffrey R. Spedding
    • 2
  • York Winter
    • 3
    • 4
  • Anders Hedenström
    • 1
  1. 1.Department of BiologyLund UniversityLundSweden
  2. 2.Department of Aerospace and Mechanical EngineeringUniversity of Southern CaliforniaLos AngelesUSA
  3. 3.Cognitive NeurobiologyHumboldt UniversityBerlinGermany
  4. 4.NeuroCure Center of ExcellenceCharité Universitätsmedizin BerlinBerlinGermany

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