Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets
Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in terms of vorticity generation along the channel wall, captures unsteady interac...
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| Format: | Article |
| Language: | en_US |
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Cambridge University Press
2012
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| Online Access: | http://hdl.handle.net/1721.1/72353 https://orcid.org/0000-0001-8242-3290 https://orcid.org/0000-0001-8730-272X |
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| author | Schlegel, Fabrice Wee, Daehyun Marzouk, Youssef M. Ghoniem, Ahmed F. |
| author2 | Massachusetts Institute of Technology. Department of Aeronautics and Astronautics |
| author_facet | Massachusetts Institute of Technology. Department of Aeronautics and Astronautics Schlegel, Fabrice Wee, Daehyun Marzouk, Youssef M. Ghoniem, Ahmed F. |
| author_sort | Schlegel, Fabrice |
| collection | MIT |
| description | Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in terms of vorticity generation along the channel wall, captures unsteady interactions between the wall boundary layer and the jet – in particular, the separation of the wall boundary layer and its transport into the interior. For comparison, we also implement a reduced boundary condition that suppresses the separation of the wall boundary layer away from the jet nozzle. By contrasting results obtained with these two boundary conditions, we characterize near-field vortical structures formed as the wall boundary layer separates on the backside of the jet. Using various Eulerian and Lagrangian diagnostics, it is demonstrated that several near-wall vortical structures are formed as the wall boundary layer separates. The counter-rotating vortex pair, manifested by the presence of vortices aligned with the jet trajectory, is initiated closer to the jet exit. Moreover tornado-like wall-normal vortices originate from the separation of spanwise vorticity in the wall boundary layer at the side of the jet and from the entrainment of streamwise wall vortices in the recirculation zone on the lee side. These tornado-like vortices are absent in the case where separation is suppressed. Tornado-like vortices merge with counter-rotating vorticity originating in the jet shear layer, significantly increasing wall-normal circulation and causing deeper jet penetration into the crossflow stream. |
| first_indexed | 2024-09-23T10:08:52Z |
| format | Article |
| id | mit-1721.1/72353 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:08:52Z |
| publishDate | 2012 |
| publisher | Cambridge University Press |
| record_format | dspace |
| spelling | mit-1721.1/723532022-09-30T19:09:08Z Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets Schlegel, Fabrice Wee, Daehyun Marzouk, Youssef M. Ghoniem, Ahmed F. Massachusetts Institute of Technology. Department of Aeronautics and Astronautics Massachusetts Institute of Technology. Department of Mechanical Engineering Marzouk, Youssef M. Schlegel, Fabrice Marzouk, Youssef M. Ghoniem, Ahmed F. Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in terms of vorticity generation along the channel wall, captures unsteady interactions between the wall boundary layer and the jet – in particular, the separation of the wall boundary layer and its transport into the interior. For comparison, we also implement a reduced boundary condition that suppresses the separation of the wall boundary layer away from the jet nozzle. By contrasting results obtained with these two boundary conditions, we characterize near-field vortical structures formed as the wall boundary layer separates on the backside of the jet. Using various Eulerian and Lagrangian diagnostics, it is demonstrated that several near-wall vortical structures are formed as the wall boundary layer separates. The counter-rotating vortex pair, manifested by the presence of vortices aligned with the jet trajectory, is initiated closer to the jet exit. Moreover tornado-like wall-normal vortices originate from the separation of spanwise vorticity in the wall boundary layer at the side of the jet and from the entrainment of streamwise wall vortices in the recirculation zone on the lee side. These tornado-like vortices are absent in the case where separation is suppressed. Tornado-like vortices merge with counter-rotating vorticity originating in the jet shear layer, significantly increasing wall-normal circulation and causing deeper jet penetration into the crossflow stream. United States. Dept. of Energy. Office of Science (MICS) (Grant Number DE-FG02-98ER25355) 2012-08-27T19:19:49Z 2012-08-27T19:19:49Z 2011-04 2010-11 Article http://purl.org/eprint/type/JournalArticle 0022-1120 1469-7645 http://hdl.handle.net/1721.1/72353 Schlegel, Fabrice et al. “Contributions of the Wall Boundary Layer to the Formation of the Counter-rotating Vortex Pair in Transverse Jets.” Journal of Fluid Mechanics 676 (2011): 461–490. https://orcid.org/0000-0001-8242-3290 https://orcid.org/0000-0001-8730-272X en_US http://dx.doi.org/10.1017/jfm.2011.59 Journal of Fluid Mechanics Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Cambridge University Press MIT web domain |
| spellingShingle | Schlegel, Fabrice Wee, Daehyun Marzouk, Youssef M. Ghoniem, Ahmed F. Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets |
| title | Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets |
| title_full | Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets |
| title_fullStr | Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets |
| title_full_unstemmed | Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets |
| title_short | Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets |
| title_sort | contributions of the wall boundary layer to the formation of the counter rotating vortex pair in transverse jets |
| url | http://hdl.handle.net/1721.1/72353 https://orcid.org/0000-0001-8242-3290 https://orcid.org/0000-0001-8730-272X |
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