Knudsen, Henning A.; Werth, Jochen; Wolf, Dietrich:

Failure and success of hydrodynamic interaction models

In: The European physical journal. E, Soft matter, Jg. 27 (2008) ; Nr. 2, S. 161-170
ISSN: 1292-895X, 1292-8941
Zeitschriftenaufsatz / Fach: Physik
Zentrale wissenschaftliche Einrichtungen » Center for Nanointegration Duisburg-Essen (CeNIDE)
In suspensions with charged particles, electrostatic forces and hydrodynamic interactions are
both important to describe the system.We study different models of hydrodynamic interaction for monopolarly
charged particles in a non-polar liquid. In this case, there is no screening of the Coulomb repulsion, so
the repulsion between all pairs must be taken into account. The particles are expected to drift away from
each other, however at a lower rate when hydrodynamic interaction between the particles is taken into
account. Existing, frequently used models of hydrodynamic interactions tend to overestimate the slowing
down of the charged particles, even to the extent that the particles effectively attract each other. This is
demonstrated for some selected particle setups. We find that these anomalies even occur in dilute systems,
if they contain sufficiently many particles. We explain why these anomalies can be avoided by an approach,
in which the superposition of interactions is done in the friction tensor instead of the mobility tensor.