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Experimental analysis of the flow field over a novel owl based airfoil

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Abstract

The aerodynamics of a newly constructed wing model the geometry of which is related to the wing of a barn owl is experimentally investigated. Several barn owl wings are scanned to obtain three-dimensional surface models of natural wings. A rectangular wing model with the general geometry of the barn owl but without any owl-specific structure being the reference case for all subsequent measurements is investigated using pressure tabs, oil flow pattern technique, and particle-image velocimetry. The main flow feature of the clean wing is a transitional separation bubble on the suction side. The size of the bubble depends on the Reynolds number and the angle of attack, whereas the location is mainly influenced by the angle of attack. Next, a second model with a modified surface is considered and its influence on the flow field is analyzed. Applying a velvet onto the suction side drastically reduces the size of this separation at moderate angles of attack and higher Reynolds numbers.

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Acknowledgments

This work has been funded by the Deutsche Forschungsgemeinschaft in the priority research program "SPP 1207 Strömungsbeeinflussung in der Natur und Technik" under grant number SCHR 309/35.

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Authors and Affiliations

  1. Institute of Aerodynamics, Wüllnerstr. 5a, 52062, Aachen, Germany

    Stephan Klän, Michael Klaas & Wolfgang Schröder

  2. Institute of Biology II, Kopernikusstr. 16, 52074, Aachen, Germany

    Thomas Bachmann & Hermann Wagner

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  1. Stephan Klän
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  2. Thomas Bachmann
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  3. Michael Klaas
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  4. Hermann Wagner
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  5. Wolfgang Schröder
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Correspondence to Stephan Klän.

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Klän, S., Bachmann, T., Klaas, M. et al. Experimental analysis of the flow field over a novel owl based airfoil. Exp Fluids 46, 975–989 (2009). https://doi.org/10.1007/s00348-008-0600-7

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  • DOI: https://doi.org/10.1007/s00348-008-0600-7

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