Contrasting turbulence in stably stratified flows and thermal convection

Abstract

In this paper, the properties of stably stratified turbulence (SST) and turbulent thermal convection are contrasted. A key difference between these flows is the sign of the kinetic energy feed by buoyancy, ${\mathcal{F}}_B$. For SST, ${\mathcal{F}}_B<0$ due to its stable nature; consequently, the kinetic energy flux ${\Pi }_u(k)$ decreases with wavenumber $k$ that leads to a steep kinetic energy spectrum, $E_u(k)\sim k^{-11/5}$. Turbulent convection is unstable, hence ${\mathcal{F}}_B>0$ that leads to an increase of ${\Pi }_u(k)$ with $k$; this increase however is marginal due to relatively weak buoyancy, hence $E_u(k)\sim k^{-5/3}$, similar to that in hydrodynamic turbulence. This paper also describes the conserved fluxes for the above systems.

to appear in Physica Scripta

References in corpus (4)

• Energy Spectrum of Buoyancy-Driven Turbulence
• Scaling of large-scale quantities in Rayleigh-Bénard convection
• Evidence for Bolgiano-Obukhov scaling in rotating stratified turbulence using high-resolution direct numerical simulations
• A Shell Model for Buoyancy-Driven Turbulence

Cited by in corpus (3)

• Variable energy flux in turbulence
• Prandtl number dependence of the small-scale properties in turbulent Rayleigh-Bénard convection
• Direct driving of simulated planetary jets by upscale energy transfer