DETAILED INVESTIGATION OF ENERGY TRANSFERS IN HOMOGENEOUS STRATIFIED TURBULENCE

This paper investigates some irreversible mechanisms occurring in homo geneous stably stratified turbulent flows. In terms of the eigenmodes of the linear regime, the velocity-temperature field is decomposed int o a vortex and two wavy components. Using an eddy-damped quasinormal M arkovian (EDQNM) closure with the axisymmetry hypothesis, an analysis of the anisotropic energy transfers between the vortex kinetic energy, the wave kinetic and potential energy is made. Within the light of tr iadic exchanges, and by analogy of the resonance condition for three l inearly interacting gravity waves, the closure model allows one to com pute the detailed transfers for eight types of interactions. Results o f the calculations include time evolution plots, for the isotropic clo sure model as well as two different types of the anisotropic closure. The pure vortical interactions are shown to be responsible for the irr eversible anisotropic structure created by stable stratification, and this structure prevents the inverse cascade of two-dimensional turbule nce.