Large-eddy simulation of decaying stratified turbulence

Large-eddy simulations (LESs) of homogeneous, initially isotropic turbulence decaying in a stratified environment were performed using an isotropic sub-grid scale model and compared to previously reported direct numerical simulation (DNS) results. The evolution of potential and kinetic energy, as well as key similarity parameters dependent on velocity fluctuations, turbulent kinetic energy dissipation rate, and turbulence length scales, were analyzed to assess the performance of the model in a stratified flow where anisotropy extends to very small scales. Favorable agreement between LES and DNS results was found, despite the Ozmidov scale, which characterizes the size of the smallest anisotropic eddies, not being resolved and the buoyancy length scale, at which buoyancy-induced Kelvin-Helmholtz instabilities develop, being marginally resolved.