Activity induced turbulence in driven active matter

TL;DR

This paper explores turbulence in driven active matter, revealing different energy spectra depending on the regime, and discusses the transition between these regimes along with experimental implications.

Contribution

It identifies a new turbulence universality class with a 7/5 energy spectrum in stratified active matter and analyzes the crossover between different turbulence regimes.

Findings

In the mixing limit, the energy spectrum follows the Kolmogorov 5/3 law.

In the stratified limit, a new 7/5 law governs the turbulence.

The paper discusses the crossover between these turbulence regimes.

Abstract

Turbulence in driven stratified active matter is considered. The relevant parameters characterizing the problem are the Reynolds number Re and an active matter Richardson-like number,R. In the mixing limit,Re>>1, R<<1, we show that the standard Kolmogorov energy spectrum 5/3 law is realized. On the other hand, in the stratified limit, Re>>1,R>>1, there is a new turbulence universality class with a 7/5 law. The crossover from one regime to the other is discussed in detail. Experimental predictions and probes are also discussed.