On the internal vorticity and density structures of miscible thermals
Miscible thermals are formed by instantaneously releasing a finite volume of buoyant fluid into stagnant ambient. Their subsequent motion is then driven by the buoyancy convection. The gross characteristics (e.g. overall size and velocity) of a thermal have been well studied and reported to be self-...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2014
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| Online Access: | https://hdl.handle.net/10356/101377 http://hdl.handle.net/10220/18396 |
| _version_ | 1811694786666561536 |
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| author | Lai, Adrian C. H. Zhao, Bing Adams, E. Eric Law, Adrian Wing-Keung |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Lai, Adrian C. H. Zhao, Bing Adams, E. Eric Law, Adrian Wing-Keung |
| author_sort | Lai, Adrian C. H. |
| collection | NTU |
| description | Miscible thermals are formed by instantaneously releasing a finite volume of buoyant fluid into stagnant ambient. Their subsequent motion is then driven by the buoyancy convection. The gross characteristics (e.g. overall size and velocity) of a thermal have been well studied and reported to be self-similar. However, there have been few studies concerning the internal structure. Here, turbulent miscible thermals (with initial density excess of 5 % and Reynolds number around 2100) have been investigated experimentally through a large number of realizations. The vorticity and density fields were quantified separately by particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) techniques. Ensemble-averaged data of the transient development of the miscible thermals are presented. Major outcomes include: (i) validating Turner’s assumption of constant circulation within a buoyant vortex ring; (ii) measuring the vorticity and density distributions within the miscible thermal; (iii) quantifying the effect of baroclinicity on the generation and destruction of vorticity within the thermal; and (iv) identifying the significantly slower decay rate of the peak density as compared to the mean. |
| first_indexed | 2024-10-01T07:13:07Z |
| format | Journal Article |
| id | ntu-10356/101377 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T07:13:07Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | ntu-10356/1013772020-03-07T11:43:45Z On the internal vorticity and density structures of miscible thermals Lai, Adrian C. H. Zhao, Bing Adams, E. Eric Law, Adrian Wing-Keung School of Civil and Environmental Engineering DRNTU::Engineering::Civil engineering Miscible thermals are formed by instantaneously releasing a finite volume of buoyant fluid into stagnant ambient. Their subsequent motion is then driven by the buoyancy convection. The gross characteristics (e.g. overall size and velocity) of a thermal have been well studied and reported to be self-similar. However, there have been few studies concerning the internal structure. Here, turbulent miscible thermals (with initial density excess of 5 % and Reynolds number around 2100) have been investigated experimentally through a large number of realizations. The vorticity and density fields were quantified separately by particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) techniques. Ensemble-averaged data of the transient development of the miscible thermals are presented. Major outcomes include: (i) validating Turner’s assumption of constant circulation within a buoyant vortex ring; (ii) measuring the vorticity and density distributions within the miscible thermal; (iii) quantifying the effect of baroclinicity on the generation and destruction of vorticity within the thermal; and (iv) identifying the significantly slower decay rate of the peak density as compared to the mean. Published version 2014-01-03T08:14:33Z 2019-12-06T20:37:29Z 2014-01-03T08:14:33Z 2019-12-06T20:37:29Z 2013 2013 Journal Article Zhao, B., Law, A. W. K., Lai, A. C. H., & Adams, E. E. (2013). On the internal vorticity and density structures of miscible thermals. Journal of fluid mechanics, 722, R5-. https://hdl.handle.net/10356/101377 http://hdl.handle.net/10220/18396 10.1017/jfm.2013.158 en Journal of fluid mechanics © 2013 Cambridge University Press. This paper was published in Journal of Fluid Mechanics and is made available as an electronic reprint (preprint) with permission of Cambridge University Press. The paper can be found at the following official DOI: [http://dx.doi.org/10.1017/jfm.2013.158]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. application/pdf |
| spellingShingle | DRNTU::Engineering::Civil engineering Lai, Adrian C. H. Zhao, Bing Adams, E. Eric Law, Adrian Wing-Keung On the internal vorticity and density structures of miscible thermals |
| title | On the internal vorticity and density structures of miscible thermals |
| title_full | On the internal vorticity and density structures of miscible thermals |
| title_fullStr | On the internal vorticity and density structures of miscible thermals |
| title_full_unstemmed | On the internal vorticity and density structures of miscible thermals |
| title_short | On the internal vorticity and density structures of miscible thermals |
| title_sort | on the internal vorticity and density structures of miscible thermals |
| topic | DRNTU::Engineering::Civil engineering |
| url | https://hdl.handle.net/10356/101377 http://hdl.handle.net/10220/18396 |
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