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Title: Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.

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.

Authors:
; ; ; ;  [1]
  1. Materials Science Division
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1015944
Report Number(s):
ANL/MSD/JA-68791
Journal ID: 1539-3755; TRN: US201112%%78
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Phys. Rev. Lett.
Additional Journal Information:
Journal Volume: 83; Journal Issue: May 2011
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ASYMPTOTIC SOLUTIONS; BACILLUS SUBTILIS; BACTERIA; FLUIDS; HYDRODYNAMICS; MOTION; SIMULATION; VISCOSITY

Citation Formats

Ryan, S D, Haines, B M, Berlyand, L V, Ziebert, F, Aranson, I S, Pennsylvania State Univ.), and UMR CNRS). Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.. United States: N. p., 2011. Web. doi:10.1103/PhysRevE.83.050904.
Ryan, S D, Haines, B M, Berlyand, L V, Ziebert, F, Aranson, I S, Pennsylvania State Univ.), & UMR CNRS). Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.. United States. doi:10.1103/PhysRevE.83.050904.
Ryan, S D, Haines, B M, Berlyand, L V, Ziebert, F, Aranson, I S, Pennsylvania State Univ.), and UMR CNRS). Sun . "Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.". United States. doi:10.1103/PhysRevE.83.050904.
@article{osti_1015944,
title = {Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.},
author = {Ryan, S D and Haines, B M and Berlyand, L V and Ziebert, F and Aranson, I S and Pennsylvania State Univ.) and UMR CNRS)},
abstractNote = {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.},
doi = {10.1103/PhysRevE.83.050904},
journal = {Phys. Rev. Lett.},
number = May 2011,
volume = 83,
place = {United States},
year = {2011},
month = {5}
}