Physical regimes and dimensional structure of rotating turbulence

Numerical simulations of rotating turbulence have given rise to ''unexpected results'': An increasing Omega did not lead to the ''expected'' route to a 2D state. A recent model of turbulence leads to a new number N = K(nu Omega)(-1) (K and nu are turbulent kinetic energy and viscosity) so that DNS (direct numerical simulation) and LES (large eddy simulation) correspond to N < 1 and N > 1. In the first case, the energy cascade is suppressed, while in the second case there exists an inertial spectrum which is an equilibrium of quasi-2D-3D modes. With these ingredients, we reproduce DNS and LES data.