Feather roughness reduces flow separation during low Reynolds number glides of swifts

The Journal of Experimental Biology
Evelien van BokhorstDavid Lentink

Abstract

Swifts are aerodynamically sophisticated birds with a small arm and large hand wing that provides them with exquisite control over their glide performance. However, their hand wings have a seemingly unsophisticated surface roughness that is poised to disturb flow. This roughness of about 2% chord length is formed by the valleys and ridges of overlapping primary feathers with thick protruding rachides, which make the wing stiffer. An earlier flow study of laminar-turbulent boundary layer transition over prepared swift wings suggested that swifts can attain laminar flow at a low angle of attack. In contrast, aerodynamic design theory suggests that airfoils must be extremely smooth to attain such laminar flow. In hummingbirds, which have similarly rough wings, flow measurements on a 3D printed model suggest that the flow separates at the leading edge and becomes turbulent well above the rachis bumps in a detached shear layer. The aerodynamic function of wing roughness in small birds is, therefore, not fully understood. Here, we performed particle image velocimetry and force measurements to compare smooth versus rough 3D-printed models of the swift hand wing. The high-resolution boundary layer measurements show that the flow over r...Continue Reading

References

Jul 1, 1995·Journal of Morphology·F E Fish, J M Battle
Jun 7, 2000·Die Naturwissenschaften·D W BechertR Meyer
Dec 14, 2004·Science·J J VidelerG D E Povel
Apr 27, 2007·Nature·D LentinkJ L van Leeuwen
Mar 21, 2008·Physical Review Letters·Ernst A van NieropMichael P Brenner
Jul 28, 2009·Journal of Theoretical Biology·Won-Kap KimDoyoung Byun
Aug 3, 2010·Journal of Theoretical Biology·David-Elie Levy, Avraham Seifert
Sep 22, 2010·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·Brian Dean, Bharat Bhushan
Jan 14, 2011·The Journal of Experimental Biology·P Henningsson, A Hedenström
Sep 22, 2012·The Journal of Experimental Biology·Yossef Elimelech, Charles P Ellington
Apr 8, 2014·Current Biology : CB·Jimmy A McGuireRobert Dudley
Jun 26, 2014·PloS One·David Lentink, Roeland de Kat
Aug 1, 2014·Journal of the Royal Society, Interface·Jan W KruytDavid Lentink

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Citations

Apr 1, 2016·The Journal of Experimental Biology·Diana D Chin, David Lentink
Oct 11, 2017·Royal Society Open Science·Masateru MaedaHao Liu
Oct 28, 2019·Nature Communications·Xiaotian ZhangMattia Gazzola
Jun 9, 2017·Journal of the Royal Society, Interface·Diana D ChinDavid Lentink
Aug 8, 2019··G. Pranay ChowdaryS. V. Shriram
Jun 15, 2019··Geoffrey R. SpeddingYohanna G. Hanna

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