Structure of unsteady stably stratified turbulence with mean shear

Buoyancy generated turbulence in stably stratified flow with shear

The energy evolution in buoyancy-generated turbulence subjected to shear depends on the gradient Richardson number Ri and the stratification number St, which is a ratio of the time scale of the initial buoyancy fluctuations to the time scale of the mean stratification. During an initial period, the flow state evolves as in the unsheared case. After this period, shear generates fluctuating veloc...

Temperature front formation in stably stratified turbulence

Temperature fronts and associated cliff-ramp structures in stably stratified turbulence are investigated using DNS of the Navier-Stokes equations under the Bousinesq approximation. Vertical profiles of temperature fluctuations show sawtooth wave structures which result in a skewed PDF of the derivative of temperature fluctuation in the z-direction. The mechanisms for generating and maintaining ...

Lagrangian mixing in decaying stably stratified turbulence

Direct numerical simulations are used to study mixing and dispersion in decaying stably stratified turbulence from a Lagrangian perspective. The change in density of fluid particles owing to small-scale mixing is extracted from the simulations to provide insight into the mixing process. These changes are driven by temporally and spatially intermittent events that are strongly suppressed as the ...

The effect of nonvertical shear on turbulence in a stably stratified medium

Preferential concentration of heavy particles in stably stratified turbulence.

The effect of preferential concentration of heavy particles in a homogeneous stably stratified turbulent flow is studied by means of direct numerical simulations. Particle distributions show different clustering patterns in horizontal and vertical directions, thereby representing the anisotropy of the flow. Preferential concentration in stably stratified turbulence can be quantified using 2D an...