Critical balance and scaling of strongly stratified turbulence at low Prandtl number

On the turbulent Prandtl number in homogeneous stably stratified turbulence

In this paper, we derive a general relationship for the turbulent Prandtl number Pr t for homogeneous stably stratified turbulence from the turbulent kinetic energy and scalar variance equations. A formulation for the turbulent Prandtl number, Pr t , is developed in terms of a mixing length scale LM and an overturning length scale LE , the ratio of the mechanical (turbulent kinetic energy) deca...

Computational Study of a Weakly Compressible Mixing Barrier in Low Prandtl Number, Strongly Stratified Fluids

The effects of weak compressibility in the evolution of a fluid governed by the anelastic fluid equations are explored computationally. The basis for this study is a careful determination of the role which the anelastic divergence constraint plays in the evolution of a periodic array of interacting vortices. Our numerical studies address a blocking phenomenon occurring in strongly stratified fl...

Critical balance in magnetohydrodynamic, rotating and stratified turbulence: towards a universal scaling conjecture

Turbulence, mixing and Prandtl number effects in stratified plane Couette flows

We report direct numerical simulations (DNS) of stratified plane Couette (SPC) flows in both continuous and layered stratifications for a wide range of Prandtl number Pr from 0.7, 7 to 70. In the continuously stratified set-up, Pr has a significant impact on the momentum and heat fluxes across the flow. Variations of these fluxes then modifies the turbulence characteristics in the way that is c...

Cascades and dissipation ratio in rotating magnetohydrodynamic turbulence at low magnetic Prandtl number.

A phenomenology of isotropic magnetohydrodynamic (MHD) turbulence subject to both rotation and applied magnetic field is presented. It is assumed that the triple correlation decay time is the shortest between the eddy turn-over time and the ones associated to the rotating frequency and the Alfvén wave period. For Pm=1 it leads to four kinds of piecewise spectra, depending on four parameters: in...