https://doi.org/10.1140/epje/i2012-12098-5
Regular Article
Bulk rheology and microrheology of active fluids
1
SUPA, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, EH9 3JZ, Edinburgh, UK
2
EPCC, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, EH9 3JZ, Edinburgh, UK
* e-mail: dmarendu@ph.ed.ac.uk
Received:
10
April
2012
Revised:
14
August
2012
Accepted:
24
August
2012
Published online:
4
October
2012
We simulate macroscopic shear experiments in active nematics and compare them with microrheology simulations where a spherical probe particle is dragged through an active fluid. In both cases we define an effective viscosity: in the case of bulk shear simulations this is the ratio between shear stress and shear rate, whereas in the microrheology case it involves the ratio between the friction coefficient and the particle size. We show that this effective viscosity, rather than being solely a property of the active fluid, is affected by the way chosen to measure it, and strongly depends on details such as the anchoring conditions at the probe surface and on both the system size and the size of the probe particle.
Key words: Topical contribution
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2012