Self-similar regimes in Unstably Stratified Homogeneous Turbulence

Abstract

Unstably stratified homogeneous turbulence develops at late time a self-similar dynamics characterized by an exponential growth of turbulent quantities. It is believed from recent theoretical studies that different growth rates are possible, depending on the initial distribution of energy at large scales. In order to confirm these predictions, we run both highly resolved direct numerical simulations and a spectral model based on an eddy-damped quasi-normal closure. In addition to confirming the influence of initial conditions, our study sheds light on the anisotropic structures of the self-similar regimes.