Prandtl number dependence of stratified turbulence

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...

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...

Prandtl number dependence of unsteady natural convection along a vertical plate in a stably stratified fluid

The Prandtl number dependence of unsteady laminar natural convection along an infinite vertical plate in a thermally stratified fluid is investigated. Flows are induced by an impulsive (step) change in plate temperature and by a suddenly imposed plate heat flux. Analytical solutions of the viscous equations of motion and thermodynamic energy are obtained for Prandtl numbers near unity by the me...

Effect of the Prandtl number on a stratified turbulent wake

The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks

The magnetic Prandtl number PrM is the ratio of viscosity to resistivity. In astrophysical disks the diffusion of angular momentum (viscosity) and magnetic fields (resistivity) are controlled by turbulence. Phenomenological models of the evolution of large scale poloidal magnetic fields in disks suggest that the turbulent magnetic Prandtl number PrM,T controls the rate of escape of vertical fie...