Eur. Phys. J. E (2018) 41: 21
https://doi.org/10.1140/epje/i2018-11625-8

Regular Article

Vortex dynamics and Lagrangian statistics in a model for active turbulence

Max Planck Institute for Dynamics and Self-Organization (MPI DS), Am Faßberg 17, 37077, Göttingen, Germany

^* e-mail: michael.wilczek@ds.mpg.de

Received: 26 September 2017
Accepted: 18 January 2018
Published online: 14 February 2018

Abstract

Cellular suspensions such as dense bacterial flows exhibit a turbulence-like phase under certain conditions. We study this phenomenon of “active turbulence” statistically by using numerical tools. Following Wensink et al. (Proc. Natl. Acad. Sci. U.S.A. 109, 14308 (2012)), we model active turbulence by means of a generalized Navier-Stokes equation. Two-point velocity statistics of active turbulence, both in the Eulerian and the Lagrangian frame, is explored. We characterize the scale-dependent features of two-point statistics in this system. Furthermore, we extend this statistical study with measurements of vortex dynamics in this system. Our observations suggest that the large-scale statistics of active turbulence is close to Gaussian with sub-Gaussian tails.