Artículos de revistas
Inverse cascades and resonant triads in rotating and stratified turbulence
Fecha
2017-11Registro en:
Oks, D.; Mininni, Pablo Daniel; Marino, R.; Pouquet, A.; Inverse cascades and resonant triads in rotating and stratified turbulence; American Institute of Physics; Physics of Fluids; 29; 11; 11-2017; 1-18; 111109
1070-6631
1089-7666
CONICET Digital
CONICET
Autor
Oks, D.
Mininni, Pablo Daniel
Marino, R.
Pouquet, A.
Resumen
Kraichnan’s seminal ideas on inverse cascades yielded new tools to study common phenomena in geophysical turbulent flows. In the atmosphere and the oceans, rotation and stratification result in a flow that can be approximated as two-dimensional at very large scales but which requires considering three-dimensional effects to fully describe turbulent transport processes and non-linear phenomena. Motions can thus be classified into two classes: fast modes consisting of inertia-gravity waves and slow quasi-geostrophic modes for which the Coriolis force and horizontal pressure gradients are close to balance. In this paper, we review previous results on the strength of the inverse cascade in rotating and stratified flows and then present new results on the effect of varying the strength of rotation and stratification (measured by the inverse Prandtl ratio N/f, of the Coriolis frequency to the Brunt-Väisäla frequency) on the amplitude of the waves and on the flow quasi-geostrophic behavior. We show that the inverse cascade is more efficient in the range of N/f for which resonant triads do not exist, /2≤N/f≤21/2≤N/f≤2. We then use the spatio-temporal spectrum to show that in this range slow modes dominate the dynamics, while the strength of the waves (and their relevance in the flow dynamics) is weaker.