title: Fluid dynamics of bacterial turbulence.
abstract: Self-sustained turbulent structures have been observed in a wide range of living fluids, yet no quantitative theory exists to explain their properties. We report experiments on active turbulence in highly concentrated 3D suspensions of Bacillus subtilis and compare them with a minimal fourth-order vector-field theory for incompressible bacterial dynamics. Velocimetry of bacteria and surrounding fluid, determined by imaging cells and tracking colloidal tracers, yields consistent results for velocity statistics and correlations over 2 orders of magnitude in kinetic energy, revealing a decrease of fluid memory with increasing swimming activity and linear scaling between kinetic energy and enstrophy. The best-fit model allows for quantitative agreement with experimental data.
authors.affiliation: DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom.
authors.forename: Jörn
authors.initials: J
authors.lastname: Dunkel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Heidenreich
authors.forename: Knut
authors.initials: K
authors.lastname: Drescher
authors.forename: Henricus H
authors.initials: HH
authors.lastname: Wensink
authors.forename: Markus
authors.initials: M
authors.lastname: Bär
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Goldstein
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry* / Q000502:physiology*; D001431:Bacteriological Techniques / Q000379:methods; D003102:Colloids / Q000737:chemistry; D003198:Computer Simulation; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D008954:Models, Biological
chemical_list: D003102:Colloids