Skip to content

Research at St Andrews

An exact steadily rotating surface quasi-geostrophic elliptical vortex

Research output: Contribution to journalArticle

Abstract

An elliptical region having a particular distribution of anomalous buoyancy or temperature at the surface of an otherwise unbounded rotating stratified fluid is shown to steadily rotate under the quasi-geostrophic approximation. The particular distribution is proportional to the vertical thickness of an ellipsoid, divided by its mean thickness, in the limit of vanishing thickness. The steady rotation of this structure or vortex is assured by the known steady rotation of any ellipsoid, and can be obtained by an appropriate limit. It is found by numerical experimentation that this vortex is stable if its minor to major aspect ratio lambda exceeds 0.427, approximately. Notably, a two-dimensional elliptical vortex (having uniform vorticity) is stable for lambda > 41/3. Instabilities of surface vortices are characterised by the ejection of a weak tongue of buoyancy, which subsequently rolls up into a street of weak vortices. The main vortex is thereby reduced in aspect ratio and remains robust for long times.

Close

Details

Original languageEnglish
Pages (from-to)368-376
Number of pages9
JournalGeophysical and Astrophysical Fluid Dynamics
Volume105
Issue number4-5
DOIs
StatePublished - 2011

    Research areas

  • Surface, Quasi-geostrophic, Steady-state, Elliptical vortex, ELLIPSOIDAL VORTICES, STRATIFIED FLUID, CONTOUR DYNAMICS, SHEAR-FLOW, MODEL, STABILITY, ALGORITHM, EVOLUTION, MOTION, STRAIN

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. On the regularity of the Green-Naghdi equations for a rotating shallow fluid layer

    Dritschel, D. G. & Jalali, M. R. 19 Feb 2019 In : Journal of Fluid Mechanics. 865, p. 100-136

    Research output: Contribution to journalArticle

  2. Scale-invariant singularity of the surface quasigeostrophic patch

    Scott, R. K. & Dritschel, D. G. 28 Jan 2019 In : Journal of Fluid Mechanics. 863, 12 p., R2

    Research output: Contribution to journalArticle

  3. Imperfect bifurcation for the quasi-geostrophic shallow-water equations

    Dritschel, D. G., Hmidi, T. & Renault, C. 12 Oct 2018 In : Archive for Rational Mechanics and Analysis. 231, 3, p. 1853-1915 63 p.

    Research output: Contribution to journalArticle

Related by journal

  1. Geophysical and Astrophysical Fluid Dynamics (Journal)

    Priest, E. R. (Member of editorial board)
    1998 → …

    Activity: Publication peer-review and editorial workEditor of research journal

  2. Geophysical and Astrophysical Fluid Dynamics (Journal)

    Hood, A. W. (Editor)
    1980 → …

    Activity: Publication peer-review and editorial workEditor of research journal

Related by journal

ID: 16904356