Distributed chaos tuned to large scale coherent motions in turbulence

TL;DR

This paper demonstrates through simulations and experiments that distributed chaos in turbulence is often synchronized with large-scale coherent motions, involving symmetry breaking and two tuning mechanisms.

Contribution

It reveals the connection between distributed chaos and large-scale coherent structures in anisotropic turbulence, highlighting two tuning mechanisms and symmetry breaking effects.

Findings

Distributed chaos is tuned to large-scale motions in turbulence.

Two tuning mechanisms: fundamental frequency and subharmonic.

Symmetry breaking accompanies the tuning process.

Abstract

It is shown, using direct numerical simulations and laboratory experiments data, that distributed chaos is often tuned to large scale coherent motions in anisotropic inhomogeneous turbulence. The examples considered are: fully developed turbulent boundary layer (range of coherence: $14 < y^{+} < 80$), turbulent thermal convection (in a horizontal cylinder), and Cuette-Taylor flow. Two ways of the tuning have been described: one via fundamental frequency (wavenumber) and another via subharmonic (period doubling). For the second way the large scale coherent motions are a natural component of distributed chaos. In all considered cases spontaneous breaking of space translational symmetry is accompanied by reflexional symmetry breaking.