Amplitude of undulating fin in the vicinity of a wall: Influence of unsteady wall effect on marine propulsion
To investigate the role of the amplitude of an object under the unsteady wall effect in fluid dynamics, the authors modelled an undulating fin near a wall in a two-dimensional Cartesian coordinate system. The fin was tethered in a uniform flow and controlled by a user-defined function program. The unsteady wall effect improved the propulsion force and propulsion efficiency at different amplitudes, but the lift force behaved differently. The authors determined the critical amplitude for the model, below which the lift force is positive within an appropriate off-wall distance range. At amplitudes larger than the critical amplitude and as the off-wall distance decreases, the average lift force is, however, always negative, causing the undulating fin to overturn towards the wall and lose stability. The essence of propulsion and lift variation lies in the change in the shape of the space between the wall and the fin, which affects the fluid flow structure and pressure distribution. In addition, some interesting phenomena related to the vortex core arrangement and pressure distribution were introduced at different amplitudes caused by the unsteady wall effect. The present results may provide new insights into the behaviours of benthic fish, reducing their undulating amplitudes and pitch angles near walls.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/00298018
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Supplemental Notes:
- © 2022 Elsevier Ltd. All rights reserved. Abstract reprinted with permission of Elsevier.
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Authors:
- Ren, Kai
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0000-0002-1080-0306
- Yu, Jiancheng
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0000-0003-1863-9737
- Publication Date: 2022-4-1
Language
- English
Media Info
- Media Type: Web
- Features: Figures; References; Tables;
- Pagination: 110987
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Serial:
- Ocean Engineering
- Volume: 249
- Issue Number: 0
- Publisher: Pergamon
- ISSN: 0029-8018
- EISSN: 1873-5258
- Serial URL: http://www.sciencedirect.com/science/journal/00298018
Subject/Index Terms
- TRT Terms: Amplitude (Physics); Fishes; Fluid dynamics; Ocean engineering; Propulsion; Unsteady flow
- Subject Areas: Marine Transportation; Vehicles and Equipment;
Filing Info
- Accession Number: 01843335
- Record Type: Publication
- Files: TRIS
- Created Date: Apr 25 2022 10:06AM