FN Archimer Export Format
PT J
TI Stability of an isolated pancake vortex in continuously stratified-rotating fluids
BT 
AF YIM, Eunok
   BILLANT, Paul
   MENESGUEN, Claire
AS 1:1;2:1;3:2;
FF 1:;2:;3:PDG-ODE-LOPS-OH;
C1 Ecole Polytech, CNRS, LadHyX, F-91128 Palaiseau, France.
   CNRS, IFREMER, LPO, BP 70, F-29280 Plouzane, France.
C2 CNRS, FRANCE
   IFREMER, FRANCE
SI BREST
SE PDG-ODE-LOPS-OH
UM LOPS
IN WOS Ifremer jusqu'en 2018
   copubli-france
IF 2.821
TC 24
UR https://archimer.ifremer.fr/doc/00347/45817/46635.pdf
LA English
DT Article
DE ;geophysical and geological flows;vortex flows;vortex instability
AB 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 Bu=α2Ro2/(4F2h) is larger than unity. When Bu≲0.7Ro+0.1, the Gent–McWilliams instability changes into a mixed baroclinic–Gent–McWilliams instability. Shear instability for m=2 exists when Fh/α is below a threshold depending on Ro. This condition is shown to come from confinement effects along the vertical. Shear instability transforms into a mixed baroclinic–shear instability for small Bu. The main energy source for both baroclinic–shear and baroclinic–Gent–McWilliams instabilities is the potential energy of the base flow instead of the kinetic energy for shear and Gent–McWilliams instabilities. The growth rates of these four instabilities depend mostly on Fh/α and Ro. Baroclinic instability develops when Fh/α|1+1/Ro|≳1.46 in qualitative agreement with the analytical predictions for a bounded vortex with angular velocity slowly varying along the vertical.
PY 2016
PD AUG
SO Journal Of Fluid Mechanics
SN 0022-1120
PU Cambridge Univ Press
VL 801
UT 000381017900021
BP 508
EP 553
DI 10.1017/jfm.2016.402
ID 45817
ER

EF