1.
Phys Rev Lett
; 108(3): 038101, 2012 Jan 20.
Article
in English
| MEDLINE
| ID: mdl-22400787
ABSTRACT
A suspension of bacteria in a thin channel or film subject to a gradient in the concentration of a chemoattractant, will develop, in the absence of an imposed fluid flow, a steady bacteria concentration field that depends exponentially on cross-stream position. Above a critical bacteria concentration, this quiescent base state is unstable to a steady convective motion driven by the active stresses induced by the bacteria's swimming. Unlike previously identified long-wavelength instabilities of active fluids, this instability results from coupling of the bacteria concentration field with the disturbance flow.