Flow transitions in collisions between vortex-rings and density interfaces

Flow transitions and vortical developments during vortex-ring collisions with a sharp water–oil density interface are studied using planar laser-induced fluorescence and time-resolved particle-image velocimetry techniques. Circular vortex-rings at Reynolds numbers of Re = 1000 , 2000 and 4000 collid...

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Main Authors: Yeo, Kye Wei B., Koh, J. Y., Long, J., New, Tze How
Other Authors: School of Mechanical and Aerospace Engineering
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/160898
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1608982022-08-05T07:32:31Z Flow transitions in collisions between vortex-rings and density interfaces Yeo, Kye Wei B. Koh, J. Y. Long, J. New, Tze How School of Mechanical and Aerospace Engineering Engineering::Mechanical engineering Vortex-Ring Collision Flow transitions and vortical developments during vortex-ring collisions with a sharp water–oil density interface are studied using planar laser-induced fluorescence and time-resolved particle-image velocimetry techniques. Circular vortex-rings at Reynolds numbers of Re = 1000 , 2000 and 4000 colliding with a density interface characterized by an Atwood number of approximately A= 0.045 were investigated. Results show that at Re = 1000 , collision with the density interface produces vortical structures and flow transitions that are relatively similar to those for a solid-boundary collision. However, the dynamics underlying the present vortical formations and behaviour are different from those associated with solid-boundary collisions, in that the former are driven by baroclinic vorticity generation. Flow behaviour at Re = 2000 shows more significant deformation of the density interface by the vortex-ring but overall behaviour remains comparable. Last but not least, at Re = 4000 , the largest Reynolds number investigated here, the vortex-ring penetrates the density interface almost completely. However, buoyancy effects eventually limit its penetration and reverse its translational direction, such that it crosses back into the oil layer again with its vortex core rotational senses reversed as well. At the same time, vortex-ring fluid is shed and a significant trailing-jet is left in the former’s wake. Nanyang Technological University The authors acknowledge support for the present study by the School of Mechanical & Aerospace Engineering and CN Yang Scholars" Programme at Nanyang Technological University, Singapore. Funding provided for the first author to present this work at the 15th Asian Symposium on Visualization under a School of Mechanical & Aerospace Engineering Enrichment Grant is also gratefully acknowledged. 2022-08-05T06:46:20Z 2022-08-05T06:46:20Z 2020 Journal Article Yeo, K. W. B., Koh, J. Y., Long, J. & New, T. H. (2020). Flow transitions in collisions between vortex-rings and density interfaces. Journal of Visualization, 23(5), 783-791. https://dx.doi.org/10.1007/s12650-020-00666-7 1343-8875 https://hdl.handle.net/10356/160898 10.1007/s12650-020-00666-7 2-s2.0-85087635478 5 23 783 791 en Journal of Visualization © 2020 The Visualization Society of Japan. All rights reserved.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Mechanical engineering
Vortex-Ring
Collision
spellingShingle Engineering::Mechanical engineering
Vortex-Ring
Collision
Yeo, Kye Wei B.
Koh, J. Y.
Long, J.
New, Tze How
Flow transitions in collisions between vortex-rings and density interfaces
description Flow transitions and vortical developments during vortex-ring collisions with a sharp water–oil density interface are studied using planar laser-induced fluorescence and time-resolved particle-image velocimetry techniques. Circular vortex-rings at Reynolds numbers of Re = 1000 , 2000 and 4000 colliding with a density interface characterized by an Atwood number of approximately A= 0.045 were investigated. Results show that at Re = 1000 , collision with the density interface produces vortical structures and flow transitions that are relatively similar to those for a solid-boundary collision. However, the dynamics underlying the present vortical formations and behaviour are different from those associated with solid-boundary collisions, in that the former are driven by baroclinic vorticity generation. Flow behaviour at Re = 2000 shows more significant deformation of the density interface by the vortex-ring but overall behaviour remains comparable. Last but not least, at Re = 4000 , the largest Reynolds number investigated here, the vortex-ring penetrates the density interface almost completely. However, buoyancy effects eventually limit its penetration and reverse its translational direction, such that it crosses back into the oil layer again with its vortex core rotational senses reversed as well. At the same time, vortex-ring fluid is shed and a significant trailing-jet is left in the former’s wake.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Yeo, Kye Wei B.
Koh, J. Y.
Long, J.
New, Tze How
format Article
author Yeo, Kye Wei B.
Koh, J. Y.
Long, J.
New, Tze How
author_sort Yeo, Kye Wei B.
title Flow transitions in collisions between vortex-rings and density interfaces
title_short Flow transitions in collisions between vortex-rings and density interfaces
title_full Flow transitions in collisions between vortex-rings and density interfaces
title_fullStr Flow transitions in collisions between vortex-rings and density interfaces
title_full_unstemmed Flow transitions in collisions between vortex-rings and density interfaces
title_sort flow transitions in collisions between vortex-rings and density interfaces
publishDate 2022
url https://hdl.handle.net/10356/160898
_version_ 1743119572158906368