Global vorticity shedding for a vanishing foil
Thesis (S.M. in Ocean Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2013
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| Online Access: | http://hdl.handle.net/1721.1/78192 |
| _version_ | 1826210489473957888 |
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| author | Steele, Stephanie Chin |
| author2 | Michael S. Triantafyllou. |
| author_facet | Michael S. Triantafyllou. Steele, Stephanie Chin |
| author_sort | Steele, Stephanie Chin |
| collection | MIT |
| description | Thesis (S.M. in Ocean Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. |
| first_indexed | 2024-09-23T14:50:44Z |
| format | Thesis |
| id | mit-1721.1/78192 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T14:50:44Z |
| publishDate | 2013 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/781922019-04-11T00:05:34Z Global vorticity shedding for a vanishing foil Steele, Stephanie Chin Michael S. Triantafyllou. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Mechanical Engineering. Thesis (S.M. in Ocean Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. Cataloged from PDF version of thesis. Includes bibliographical references (p. 59-60). We explore several aspects of the phenomenon we call global vorticity shedding. Global vorticity shedding occurs when an object in viscous fluid suddenly vanishes, shedding the entire boundary layer vorticity into the wake at once. In our experiments we approximate the disappearance of a towed foil by rapidly retracting the foil in the span-wise direction. Global vorticity shedding is in distinct contrast with conventional shedding, in which vorticity is shed from a body from only a few separation points into the fluid. In this work, we show that for a square-tipped vanishing foil at an angle of attack, the globally shed boundary layer vorticity forms into primary vortices, which evolve and eventually amalgamate with secondary vortices to leave two lasting vortices in the wake. The secondary vortices are a result of three-dimensionality in the flow. For a streamlined-end foil, we achieve a simpler and less three-dimensional wake with no secondary vortices, arid only one lasting vortex dominating the wake. However, due to the initial vorticity distribution near the streamlined end of the foil, the initial circulation is reduced. We also show that the lasting vortices are capable of producing reasonably large forces on a body through simple potential flow estimations, aid that vortex formation times are small, with vortices fully formed nearly instantaneously in the flow. These features are promising for a force transducer using global vorticity shedding to impart large and fast maneuvering forces on an underwater vehicle. by Stephanie Chin Steele. S.M.in Ocean Engineering 2013-03-28T18:13:15Z 2013-03-28T18:13:15Z 2012 2012 Thesis http://hdl.handle.net/1721.1/78192 830376795 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 60 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Steele, Stephanie Chin Global vorticity shedding for a vanishing foil |
| title | Global vorticity shedding for a vanishing foil |
| title_full | Global vorticity shedding for a vanishing foil |
| title_fullStr | Global vorticity shedding for a vanishing foil |
| title_full_unstemmed | Global vorticity shedding for a vanishing foil |
| title_short | Global vorticity shedding for a vanishing foil |
| title_sort | global vorticity shedding for a vanishing foil |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/78192 |
| work_keys_str_mv | AT steelestephaniechin globalvorticitysheddingforavanishingfoil |