Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current
The classical problem of flow past a cylinder is revisited in the context of understanding two oceanographic phenomena: separation of the Gulf Stream from the North American coastline at Cape Hatteras and the interaction of the Antarctic Circumpolar Current with topographic obstacles. Numerical solu...
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ftuloxford:oai:ora.ox.ac.uk:uuid:c86be995-2e9d-45ce-96ad-96b1c80dd876 2023-05-15T13:54:35+02:00 Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current Tansley, C Marshall, D 2016-07-29 https://doi.org/10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 https://ora.ox.ac.uk/objects/uuid:c86be995-2e9d-45ce-96ad-96b1c80dd876 eng eng doi:10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 https://ora.ox.ac.uk/objects/uuid:c86be995-2e9d-45ce-96ad-96b1c80dd876 https://doi.org/10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 info:eu-repo/semantics/embargoedAccess Journal article 2016 ftuloxford https://doi.org/10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 2022-06-28T20:23:42Z The classical problem of flow past a cylinder is revisited in the context of understanding two oceanographic phenomena: separation of the Gulf Stream from the North American coastline at Cape Hatteras and the interaction of the Antarctic Circumpolar Current with topographic obstacles. Numerical solutions are presented for eastward, barotropic flow past a cylinder in a β-plane channel. The solutions are dependent on two nondimensional parameters: the Reynolds number, Re, and a nondimensional β parameter, ̂b. In line with previous studies, increasing ̂b reduces the separation downstream of the cylinder but introduces a blocked stagnant region upstream of the cylinder, flanked by two inertial jets. The large ̂b limit is relevant to the interaction of the Antarctic Circumpolar Current with topographic obstacles such as the Kerguelen Plateau. However, a new regime is obtained for high Reynolds number (Re > 200) and moderate β parameter (̂b ∼ 10-100) with two separated jets downstream of the cylinder. These jets can extend a considerable distance, maintained by breaking Rossby waves in the turbulent wake of the cylinder, within which there is a downscale cascade of vorticity and an upscale cascade of energy toward the Rhines scale. Through a series of numerical experiments, the authors demonstrate the relevance of this regime to the separation of a boundary current from a cape. The implications are that Gulf Stream separation at Cape Hatteras is the consequence of both the high Reynolds number in the ocean and the moderate β parameter associated with the curvature of the coastline at Cape Hatteras. Results also suggest that geostrophic eddy fluxes are essential in maintaining a tight separated jet. Article in Journal/Newspaper Antarc* Antarctic ORA - Oxford University Research Archive Antarctic Kerguelen The Antarctic |
institution |
Open Polar |
collection |
ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
English |
description |
The classical problem of flow past a cylinder is revisited in the context of understanding two oceanographic phenomena: separation of the Gulf Stream from the North American coastline at Cape Hatteras and the interaction of the Antarctic Circumpolar Current with topographic obstacles. Numerical solutions are presented for eastward, barotropic flow past a cylinder in a β-plane channel. The solutions are dependent on two nondimensional parameters: the Reynolds number, Re, and a nondimensional β parameter, ̂b. In line with previous studies, increasing ̂b reduces the separation downstream of the cylinder but introduces a blocked stagnant region upstream of the cylinder, flanked by two inertial jets. The large ̂b limit is relevant to the interaction of the Antarctic Circumpolar Current with topographic obstacles such as the Kerguelen Plateau. However, a new regime is obtained for high Reynolds number (Re > 200) and moderate β parameter (̂b ∼ 10-100) with two separated jets downstream of the cylinder. These jets can extend a considerable distance, maintained by breaking Rossby waves in the turbulent wake of the cylinder, within which there is a downscale cascade of vorticity and an upscale cascade of energy toward the Rhines scale. Through a series of numerical experiments, the authors demonstrate the relevance of this regime to the separation of a boundary current from a cape. The implications are that Gulf Stream separation at Cape Hatteras is the consequence of both the high Reynolds number in the ocean and the moderate β parameter associated with the curvature of the coastline at Cape Hatteras. Results also suggest that geostrophic eddy fluxes are essential in maintaining a tight separated jet. |
format |
Article in Journal/Newspaper |
author |
Tansley, C Marshall, D |
spellingShingle |
Tansley, C Marshall, D Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current |
author_facet |
Tansley, C Marshall, D |
author_sort |
Tansley, C |
title |
Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current |
title_short |
Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current |
title_full |
Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current |
title_fullStr |
Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current |
title_full_unstemmed |
Flow past a cylinder on a beta plane, with application to Gulf Stream separation and the Antarctic Circumpolar Current |
title_sort |
flow past a cylinder on a beta plane, with application to gulf stream separation and the antarctic circumpolar current |
publishDate |
2016 |
url |
https://doi.org/10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 https://ora.ox.ac.uk/objects/uuid:c86be995-2e9d-45ce-96ad-96b1c80dd876 |
geographic |
Antarctic Kerguelen The Antarctic |
geographic_facet |
Antarctic Kerguelen The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
doi:10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 https://ora.ox.ac.uk/objects/uuid:c86be995-2e9d-45ce-96ad-96b1c80dd876 https://doi.org/10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 |
op_rights |
info:eu-repo/semantics/embargoedAccess |
op_doi |
https://doi.org/10.1175/1520-0485(2001)031<3274:FPACOA>2.0.CO;2 |
_version_ |
1766260579948822528 |