1. A combined rheometry and imaging study of viscosity reduction in bacterial suspensions.
- Author
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Martinez, Vincent A., Clément, Eric, Arlt, Jochen, Douarche, Carine, Dawson, Angela, Schwarz-Linek, Jana, Creppy, Adama K., kulté ty, Viktor Š, Morozov, Alexander N., Auradou, Harold, and Poon, Wilson C. K.
- Subjects
VISCOSITY ,DIAGNOSTIC imaging ,PARTICLE image velocimetry ,SYSTEMS theory - Abstract
Suspending self-propelled “pushers" in a liquid lowers its viscosity. We study how this phenomenon depends on system size in bacterial suspensions using bulk rheometry and particle-tracking rheoimaging. Above the critical bacterial volume fraction needed to decrease the viscosity to zero, ϕ
c ≈0.75%, large-scale collective motion emerges in the quiescent state, and the flow becomes nonlinear. We confirm a theoretical prediction that such instability should be suppressed by confinement. Our results also show that a recent application of active liquid-crystal theory to such systems is untenable. [ABSTRACT FROM AUTHOR]- Published
- 2020
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