Kolmogorovian active turbulence of a sparse assembly of interacting swimmers

TL;DR

This paper demonstrates experimentally that active matter composed of self-propelled particles exhibits turbulence characteristics similar to classical fluid turbulence, specifically Kolmogorov's phenomenology, suggesting a universality between these out-of-equilibrium systems.

Contribution

It provides the first experimental evidence linking active turbulence with Kolmogorov's fluid turbulence theory, highlighting a potential universality class.

Findings

Active matter shows Kolmogorov-like energy spectra.

Spatial and temporal flow patterns resemble classical turbulence.

Active turbulence may belong to the same universality class as fluid turbulence.

Abstract

Active matter, composed of self-propelled entities, forms a wide class of out-of-equilibrium systems that display striking collective behaviors among which the so-called active turbulence where spatially and time disordered flow patterns spontaneously arise in a variety of {active systems}. De facto, the active turbulence naming suggests a connection with a second seminal class of out-of-equilibrium systems, fluid turbulence, and yet of very different nature with energy injected at global system scale rather than at the elementary scale of single constituents. Indeed the existence of a possible strong-tie between active and canonical turbulence remains an open question and a field of profuse research. Using an assembly of self-propelled interfacial particles, we show experimentally that this active system shares remarkable quantitative similarities with canonical fluid turbulence, as described by the celebrated 1941 phenomenology of Kolmogorov. Making active matter entering into the universality class of fluid turbulence not only benefits to its future development but may also provide new insights for the longstanding description of turbulent flows, arguably one of the biggest remaining mysteries in classical physics.