Transition delay using biomimetic fish scale arrays.

Autor: Muthuramalingam M; School of Mathematics, Computer Science and Engineering, City, University of London, London, EC1V 0HB, UK. muthukumar.muthuramalingam@city.ac.uk., Puckert DK; Institut für Aerodynamik und Gasdynamik, Universität Stuttgart, Pfaffenwaldring 21, 70569, Stuttgart, Germany., Rist U; Institut für Aerodynamik und Gasdynamik, Universität Stuttgart, Pfaffenwaldring 21, 70569, Stuttgart, Germany., Bruecker C; School of Mathematics, Computer Science and Engineering, City, University of London, London, EC1V 0HB, UK.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2020 Sep 03; Vol. 10 (1), pp. 14534. Date of Electronic Publication: 2020 Sep 03.
DOI: 10.1038/s41598-020-71434-8
Abstrakt: Aquatic animals have developed effective strategies to reduce their body drag over a long period of time. In this work, the influence of the scales of fish on the laminar-to-turbulent transition in the boundary layer is investigated. Arrays of biomimetic fish scales in typical overlapping arrangements are placed on a flat plate in a low-turbulence laminar water channel. Transition to turbulence is triggered by controlled excitation of a Tollmien-Schlichting (TS) wave. It was found that the TS wave can be attenuated with scales on the plate which generate streamwise streaks. As a consequence, the transition location was substantially delayed in the downstream direction by 55% with respect to the uncontrolled reference case. This corresponds to a theoretical drag reduction of about 27%. We thus hypothesize that fish scales can stabilize the laminar boundary layer and prevent it from early transition, reducing friction drag. This technique can possibly be used for bio-inspired surfaces as a laminar flow control means.
Databáze: MEDLINE
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