title: Vorticity, defects and correlations in active turbulence.
abstract: We describe a numerical investigation of a continuum model of an active nematic, concentrating on the regime of active turbulence. Results are presented for the effect of three parameters, activity, elastic constant and rotational diffusion constant, on the order parameter and flow fields. Defects and distortions in the director field act as sources of vorticity, and thus vorticity is strongly correlated to the director field. In particular, the characteristic length of decay of vorticity and order parameter correlations is controlled by the defect density. By contrast, the decay of velocity correlations is determined by a balance between activity and dissipation. We highlight the role of microscopic flow generation mechanisms in determining the flow patterns and characteristic scales of active turbulence and contrast the behaviour of extensile and contractile active nematics.
authors.affiliation: The Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, UK.
authors.forename: Sumesh P
authors.initials: SP
authors.lastname: Thampi
authors.affiliation: The Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, UK.
authors.forename: Ramin
authors.initials: R
authors.lastname: Golestanian
authors.affiliation: The Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, UK j.yeomans1@physics.ox.ac.uk.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Yeomans
keywords: active turbulence; correlations; defects; vorticity