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CEE Seminar: Waves in Rotating Stratified Turbulence: Structures, Intermittency and Mixing

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Tuesday, January 22, 2019
12:00 pm - 1:00 pm
Annick Pouquet, Research Scientist, Laboratory for Atmospheric and Space Physics, Boulder, CO
CEE Spring 2019 Seminar Series

In a stratified fluid, the velocity field couples to density fluctuations, supporting inertia-gravity in the presence of rotation, with an anisotropic dispersion relation, and leading to a variety of turbulence regimes resulting from the interactions between nonlinear eddies and waves. What are the delimiting factors of these regimes, and what differentiate them? Three specific issues will be briefly analyzed: (i) structures leading to (ii) dissipation because of (iii) energy cascades.

Using simple classical models of turbulence, it can be shown phenomenologically and numerically that strong localized instabilities lead to an effective dissipation in rotating stratified turbulence (RST) which is proportional to the Froude number, that is the ratio of the wave period to the eddy turn-over time [1]. This law governs the ratio of the amount of energy going, in a constant-flux solution, to the large scales because of rotation to that going to the small scales because of stratification [2ab,3ab]. It also determines the variation.....