Direct numerical simulation of developed shear driven turbulence

Direct numerical simulation of spiral turbulence

In this paper, we present results of three-dimensional direct numerical simulations of the spiral turbulence phenomenon in a range of moderate Reynolds numbers, in which alternating intertwined helical bands of turbulent and laminar fluids coexist and propagate between two counter-rotating concentric cylinders. We show that the turbulent spiral is comprised of numerous small-scale azimuthally e...

Direct numerical simulation and large-eddy simulation of stationary buoyancy-driven turbulence

We report direct numerical simulation (DNS) and large-eddy simulation (LES) of statistically stationary buoyancy-driven turbulent mixing of an active scalar. We use an adaptation of the fringe-region technique, which continually supplies the flow with unmixed fluids at two opposite faces of a triply periodic domain in the presence of gravity, effectively maintaining an unstably stratified, but ...

Direct numerical simulation of salt sheets and turbulence in a double-diffusive shear layer

[1] We describe three-dimensional direct numerical simulations (DNS) of double-diffusively stratified flow interacting with inflectional shear. The extreme difference in diffusivity (and thus minimum length scale) between heat, salt and momentum in seawater is replicated for the first time in a three-dimensional simulation. The primary instability generates salt sheets, which are oriented paral...

Direct Numerical Simulation of Wall Turbulence with Bubbles

Probing Physics of Magnetohydrodynamic Turbulence Using Direct Numerical Simulation

The energy spectrum and the nolinear cascade rates of MHD turbulence is not clearly understood. We have addressed this problem using direct numerical simulation and analytical calculations. Our numerical simulations indicate that Kolmogorov-like phenomenology with k energy spectrum, rather than Kraichnan’s k, appears to be applicable in MHD turbulence. Here, we also construct a self-consistent ...