Universal scaling of active nematic turbulence
By Ricard Alert, J. Joanny, Jaume Casademunt. 2019
136 citations recorded by the source corpus.
A landmark of turbulence is the emergence of universal scaling laws, such as Kolmogorov’s E ( q ) ~ q −5∕3 scaling of the kinetic energy spectrum of inertial turbulence with the wavevector q . In recent years, active fluids have been shown to exhibit turbulent-like flows at low Reynolds number. However, the existence of universal scaling properties in these flows has remained unclear. To address this issue, here we propose a minimal defect-free hydrodynamic theory for two-dimensional active nematic fluids at vanishing Reynolds number. By means of large-scale simulations and analytical arguments, we show that the kinetic energy spectrum exhibits a universal scaling E ( q ) ~ q −1 at long wavelengths. We find that the energy injection due to activity has a peak at a characteristic length scale, which is selected by a nonlinear mechanism. In contrast to inertial turbulence, energy is entirely dissipated at the scale where it is injected, thus precluding energy cascades. Nevertheless, the non-local character of the Stokes flow establishes long-range velocity correlations, which lead to the scaling behaviour. We conclude that active nematic fluids define a distinct universality class of turbulence at low Reynolds number. Determining the properties that emerge from the equations that govern turbulent flow is a fundamental challenge in non-equilibrium physics. A hydrodynamic theory for two-dimensional active nematic fluids at vanishing Reynolds number is now put forward, revealing a universal scaling behaviour for this class of systems.
Subfields: Condensed Matter Physics, Physiology, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/534bc46cde7779d03a0b6804f9c77d79ee20f836
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In Condensed Matter Physics
In Statistical and Nonlinear Physics
Citations in the corpus
- Active Turbulence (2021, background): “However, symmetry arguments show that this contribution to the energy transfer vanishes identically for the statistically-isotropic turbulent state [107].”