3D Kolmogorov flow with large-scale damping

Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations.
This video shows the vorticity field of a three-dimensional Kolmogorov flow with large-scale damping on an aspect-ratio-three domain, obtained from a pseudo-spectral simulation. Planes show out-of-plane vorticity averaged over the normal direction, and the vorticity magnitude is volume-rendered.
The flow exhibits a large-scale state with three pairs of counter-rotating vortices. The small-scale turbulence,
illustrated by the volume rendering, is nearly homogenous. This is markedly different from the case without
damping (see • Video ).
Please see arxiv.org/abs/2102.07675 for further details.