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| Yim, Eunok; Billant, Paul; Menesguen, Claire. |
| This paper investigates the stability of an axisymmetric pancake vortex with Gaussian angular velocity in radial and vertical directions in a continuously stratified-rotating fluid. The different instabilities are determined as a function of the Rossby number Ro, Froude number Fh, Reynolds number Re and aspect ratio α. Centrifugal instability is not significantly different from the case of a columnar vortex due to its short-wavelength nature: it is dominant when the absolute Rossby number |Ro| is large and is stabilized for small and moderate |Ro| when the generalized Rayleigh discriminant is positive everywhere. The Gent–McWilliams instability, also known as internal instability, is then dominant for the azimuthal wavenumber m=1 when the Burger number... |
| Tipo: Text |
Palavras-chave: Geophysical and geological flows; Vortex flows; Vortex instability. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00347/45817/46635.pdf |
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| Duarte, Rui; Carton, Xavier; Capet, Xavier; Cherubin, Laurent. |
| This paper addresses the instability of a two-layer coastal current in a quasi-geostrophic model; the potential vorticity (PV) structure of this current consists in two uniform cores, located at different depths, with finite width and horizontally shifted. This shift allows both barotropic and baroclinic instability for this current. The PV cores can be like-signed or opposite-signed, leading to their vertical alignment or to their hetonic coupling. These two aspects are novel compared to previous studies. For narrow vorticity cores, short waves dominate, associated with barotropic instability; for wider cores, longer waves are more unstable and are associated with baroclinic processes. Numerical experiments were performed on the f-plane with a... |
| Tipo: Text |
Palavras-chave: Stability and instability of geophysical and astrophysical flows; Vortex flows; Rotating fluids; Stability problems; Applications to physics. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00069/17999/15673.pdf |
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