Double-diffusive transport in multicomponent vertical convection
Motivated by the ablation of vertical ice faces in salt water, we use three-dimensional direct numerical simulations to investigate the heat and salt fluxes in two-scalar vertical convection. For parameters relevant to ice-ocean interfaces in the convection-dominated regime, we observe that the sali...
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2023
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Online Access: | https://hdl.handle.net/2108/361709 https://doi.org/10.1103/PhysRevFluids.8.013501 |
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ftunivromatorver:oai:art.torvergata.it:2108/361709 2024-06-09T07:46:52+00:00 Double-diffusive transport in multicomponent vertical convection Howland (Christopher J. ) Roberto Verzicco Detlef Lohse Howland (Christopher, J) Verzicco, R Lohse, D 2023 https://hdl.handle.net/2108/361709 https://doi.org/10.1103/PhysRevFluids.8.013501 eng eng American Physical Society country:US volume:8 issue:1 journal:PHYSICAL REVIEW FLUIDS https://hdl.handle.net/2108/361709 doi:10.1103/PhysRevFluids.8.013501 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85146368499 Settore ING-IND/06 info:eu-repo/semantics/article 2023 ftunivromatorver https://doi.org/10.1103/PhysRevFluids.8.013501 2024-05-14T23:37:46Z Motivated by the ablation of vertical ice faces in salt water, we use three-dimensional direct numerical simulations to investigate the heat and salt fluxes in two-scalar vertical convection. For parameters relevant to ice-ocean interfaces in the convection-dominated regime, we observe that the salinity field drives the convection and that heat is essentially transported as a passive scalar. By varying the diffusivity ratio of heat and salt (i.e., the Lewis number Le), we identify how the different molecular diffusivities affect the scalar fluxes through the system. Away from the walls, we find that the heat transport is determined by a turbulent Prandtl number of Prt≈1 and that double-diffusive effects are practically negligible. However, the difference in molecular diffusivities plays an important role close to the boundaries. In the (unrealistic) case where salt diffused faster than heat, the ratio of salt-to-heat fluxes would scale as Le1/3, consistent with classical nested scalar boundary layers. However, in the realistic case of faster heat diffusion (relative to salt), we observe a transition towards a Le1/2 scaling of the ratio of the fluxes. This coincides with the thermal boundary layer width growing beyond the thickness of the viscous boundary layer. We find that this transition is not determined by a critical Lewis number, but rather by a critical Prandtl number Pr≈10, slightly below that for cold seawater where Pr=14. We compare our results to similar studies of sheared and double-diffusive flow under ice shelves, and discuss the implications for fluxes in large-scale ice-ocean models. By coupling our results to ice-ocean interface thermodynamics, we describe how the flux ratio impacts the interfacial salinity, and hence the strength of solutal convection and the ablation rate. Article in Journal/Newspaper Ice Shelves Universitá degli Studi di Roma "Tor Vergata": ART - Archivio Istituzionale della Ricerca Physical Review Fluids 8 1 |
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Universitá degli Studi di Roma "Tor Vergata": ART - Archivio Istituzionale della Ricerca |
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ftunivromatorver |
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English |
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Settore ING-IND/06 |
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Settore ING-IND/06 Howland (Christopher J. ) Roberto Verzicco Detlef Lohse Double-diffusive transport in multicomponent vertical convection |
topic_facet |
Settore ING-IND/06 |
description |
Motivated by the ablation of vertical ice faces in salt water, we use three-dimensional direct numerical simulations to investigate the heat and salt fluxes in two-scalar vertical convection. For parameters relevant to ice-ocean interfaces in the convection-dominated regime, we observe that the salinity field drives the convection and that heat is essentially transported as a passive scalar. By varying the diffusivity ratio of heat and salt (i.e., the Lewis number Le), we identify how the different molecular diffusivities affect the scalar fluxes through the system. Away from the walls, we find that the heat transport is determined by a turbulent Prandtl number of Prt≈1 and that double-diffusive effects are practically negligible. However, the difference in molecular diffusivities plays an important role close to the boundaries. In the (unrealistic) case where salt diffused faster than heat, the ratio of salt-to-heat fluxes would scale as Le1/3, consistent with classical nested scalar boundary layers. However, in the realistic case of faster heat diffusion (relative to salt), we observe a transition towards a Le1/2 scaling of the ratio of the fluxes. This coincides with the thermal boundary layer width growing beyond the thickness of the viscous boundary layer. We find that this transition is not determined by a critical Lewis number, but rather by a critical Prandtl number Pr≈10, slightly below that for cold seawater where Pr=14. We compare our results to similar studies of sheared and double-diffusive flow under ice shelves, and discuss the implications for fluxes in large-scale ice-ocean models. By coupling our results to ice-ocean interface thermodynamics, we describe how the flux ratio impacts the interfacial salinity, and hence the strength of solutal convection and the ablation rate. |
author2 |
Howland (Christopher, J) Verzicco, R Lohse, D |
format |
Article in Journal/Newspaper |
author |
Howland (Christopher J. ) Roberto Verzicco Detlef Lohse |
author_facet |
Howland (Christopher J. ) Roberto Verzicco Detlef Lohse |
author_sort |
Howland (Christopher J. ) |
title |
Double-diffusive transport in multicomponent vertical convection |
title_short |
Double-diffusive transport in multicomponent vertical convection |
title_full |
Double-diffusive transport in multicomponent vertical convection |
title_fullStr |
Double-diffusive transport in multicomponent vertical convection |
title_full_unstemmed |
Double-diffusive transport in multicomponent vertical convection |
title_sort |
double-diffusive transport in multicomponent vertical convection |
publisher |
American Physical Society |
publishDate |
2023 |
url |
https://hdl.handle.net/2108/361709 https://doi.org/10.1103/PhysRevFluids.8.013501 |
genre |
Ice Shelves |
genre_facet |
Ice Shelves |
op_relation |
volume:8 issue:1 journal:PHYSICAL REVIEW FLUIDS https://hdl.handle.net/2108/361709 doi:10.1103/PhysRevFluids.8.013501 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85146368499 |
op_doi |
https://doi.org/10.1103/PhysRevFluids.8.013501 |
container_title |
Physical Review Fluids |
container_volume |
8 |
container_issue |
1 |
_version_ |
1801376867824959488 |