Strongly anisotropic turbulence structure and cascade : stably-stratified and rotating flows (mainly) revisited

Claude Cambon, Laboratoire de Mécanique des Fluides et d'Acoustique (LMFA), Ecole Centrale de lyon, Ecully, France

a) Evidence for quasi- homogeneous, strongly anisotropic (until small scales), flows. From `weak' Wave-turbulence to `strong' turbulence interacting with waves : general concepts.

b) Strongly (stably) stratified flows: the toroidal cascade for 'strong' turbulence dynamics. Statistical theory versus Hydrodynamic stability for explaining the layering.

c) Rapidly rotating turbulence: inertial wave-turbulence, phase-mixing and resonant triads. Partial two-dimensionalization. Results from theory, DNS/LES, and experiments.

d) Brief survey of flow cases illustrating similar issues: Quasi-Geostrophic versus 2D cascade, MHD flows with strong axial mean magnetic field, weakly compressible turbulence.

e) Open problems: spectral transfer or 3rd order structure function for evaluating the cascade ? (Really) anisotropic Subgrid Scale modelling. Competition of waves and vortices to control the mixing.