2D and 3D Properties of Stably Stratified Turbulence

Abstract

Through interactions between the modes of “waves” and “vortices”, stably stratified turbulence exhibits characteristic features both in 2D and 3D. Using DNS of the Navier–Stokes equations coupled to an equation for temperature (the Bousinessq system), we investigate dynamical properties of stably stratified turbulence. After reviewing the importance of three characteristic length scales and their relations in stably stratified turbulence, we present numerical results showing how structures and spectra develop with the growth of the length scales. It is demonstrated that the temperature fluctuations make sharp fronts vertically which result in non-symmetric PDFs of the vertical derivative ∂zθ.

Keywords

• stratified turbulence
• buoyancy scale
• Ozmidov scale
• Kolmogorov scale
• Craya-Herring decomposition
• temperature front