The 3D structure of turbulent channels up to $\mathrm{Re}_\tau=4000$

TL;DR

This paper presents visualizations of turbulent channel flows at Reynolds numbers up to 4000, highlighting increased scale separation and dynamic complexity with higher Reynolds numbers.

Contribution

It provides time-resolved fluid dynamics videos capturing turbulence structures across a wide range of Reynolds numbers up to 4000.

Findings

Increased scale separation at higher Reynolds numbers.

Greater complexity in turbulence dynamics observed.

Visual evidence of sweeps and ejections in turbulent flows.

Abstract

Several time-resolved fluid dynamics videos of turbulent channels from $\mathrm{Re}_\tau=180$ to $\mathrm{Re}_\tau=4000$ are presented. The videos show the temporal evolution of sweeps (bluish) and ejections (reddish) in one half of the channel (only the bottom wall is shown). The color changes from dark for points close to the wall, to bright for those reaching the center of the channel. As the Reynolds number increases the scale separation becomes more clear and the complexity of the dynamics observed rises.