Viscosity of bacterial suspensions: Hydrodynamic interactions and self-induced noise

Shawn D. Ryan, Brian M. Haines, Leonid Berlyand, Falko Ziebert, Igor S. Aranson

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

The viscosity of a suspension of swimming bacteria is investigated analytically and numerically. We propose a simple model that allows for efficient computation for a large number of bacteria. Our calculations show that long-range hydrodynamic interactions, intrinsic to self-locomoting objects in a viscous fluid, result in a dramatic reduction of the effective viscosity. In agreement with experiments on suspensions of Bacillus subtilis, we show that the viscosity reduction is related to the onset of large-scale collective motion due to interactions between the swimmers. The simulations reveal that the viscosity reduction occurs only for relatively low concentrations of swimmers: Further increases of the concentration yield an increase of the viscosity. We derive an explicit asymptotic formula for the effective viscosity in terms of known physical parameters and show that hydrodynamic interactions are manifested as self-induced noise in the absence of any explicit stochasticity in the system.

Original languageEnglish (US)
Article number050904
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume83
Issue number5
DOIs
StatePublished - May 16 2011

Fingerprint

Hydrodynamic Interaction
Viscosity
hydrodynamics
viscosity
interactions
Bacteria
bacteria
Collective Motion
Stochasticity
Bacillus
Long-range Interactions
viscous fluids
Viscous Fluid
Asymptotic Formula
Explicit Formula
low concentrations
Interaction
Experiment
Simulation
simulation

All Science Journal Classification (ASJC) codes

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

Cite this

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Viscosity of bacterial suspensions : Hydrodynamic interactions and self-induced noise. / Ryan, Shawn D.; Haines, Brian M.; Berlyand, Leonid; Ziebert, Falko; Aranson, Igor S.

In: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, Vol. 83, No. 5, 050904, 16.05.2011.

Research output: Contribution to journalArticle

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