Movable shark scales act as a passive dynamic micro-roughness to control flow separation
| Autor: | Jennifer Wheelus, Jonathon A Smith, Robert E. Hueter, Amy Lang, Maria Laura Habegger, Philip J. Motta, Michael Bradshaw |
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| Rok vydání: | 2014 |
| Předmět: |
Reversed flow
Isurus Surface Properties Flow (psychology) Separation (aeronautics) Biophysics chemical and pharmacologic phenomena Biochemistry Micro roughness Flow separation Motion Hardness Skin Physiological Phenomena Materials Testing Animals Engineering (miscellaneous) Swimming biology Fish fin Mechanics biology.organism_classification Water tunnel Animal Fins Sharks Molecular Medicine Rheology human activities Geology Biotechnology Marine engineering |
| Zdroj: | Bioinspirationbiomimetics. 9(3) |
| ISSN: | 1748-3190 |
| Popis: | Shark scales on fast-swimming sharks have been shown to be movable to angles in excess of 50°, and we hypothesize that this characteristic gives this shark skin a preferred flow direction. During the onset of separation, flow reversal is initiated close to the surface. However, the movable scales would be actuated by the reversed flow thereby causing a greater resistance to any further flow reversal and this mechanism would disrupt the process leading to eventual flow separation. Here we report for the first time experimental evidence of the separation control capability of real shark skin through water tunnel testing. Using skin samples from a shortfin mako Isurus oxyrinchus, we tested a pectoral fin and flank skin attached to a NACA 4412 hydrofoil and separation control was observed in the presence of movable shark scales under certain conditions in both cases. We hypothesize that the scales provide a passive, flow-actuated mechanism acting as a dynamic micro-roughness to control flow separation. |
| Databáze: | OpenAIRE |
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