Crowe, Matthew N;
Johnson, Edward R;
(2023)
The evolution of surface quasi-geostrophic modons on sloping topography.
Journal of Fluid Mechanics
, 970
, Article A10. 10.1017/jfm.2023.607.
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Abstract
This work discusses modons, or dipolar vortices, propagating along sloping topography. Two different regimes exist, which are studied separately using the surface quasi-geostrophic equations. First, when the modon propagates in the direction opposite to topographic Rossby waves, steady solutions exist and a semi-analytical method is presented for calculating these solutions. Second, when the modon propagates in the same direction as the Rossby waves, a wave wake is generated. This wake removes energy from the modon, causing it to decay slowly. Asymptotic predictions are presented for this decay and found to agree closely with numerical simulations. Over long times, decaying vortices are found to break down due to an asymmetry resulting from the generation of waves inside the vortex. A monopolar vortex moving along a wall is shown to behave in a similar way to a dipole, though the presence of the wall is found to stabilise the vortex and prevent the long-time breakdown. The problem is equivalent mathematically to a dipolar vortex moving along a density front, hence our results apply directly to this case.
Type: | Article |
---|---|
Title: | The evolution of surface quasi-geostrophic modons on sloping topography |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1017/jfm.2023.607 |
Publisher version: | https://doi.org/10.1017/jfm.2023.607 |
Language: | English |
Additional information: | Copyright © The Author(s), 2023. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited. |
Keywords: | Geophysical and Geological Flows: Waves in rotating fluids; Geophysical and Geological Flows: Topographic effects; Vortex Flows: Vortex dynamics |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Mathematics |
URI: | https://discovery.ucl.ac.uk/id/eprint/10174201 |
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