Abstract
The shear free solid-body rotation of a ferrofluid in a magnetic field experiences a damping due to internal rotational friction. A device based on the principle of a torsional pendulum is presented. It allows us to perform direct and precise measurements of the field dependence of the genuine rotational viscosity without a disturbing shear flow. Experimental results for a moderately concentrated ferrofluid compare reasonably well with theoretical models for monodisperse ferrofluids of noninteracting rigid dipoles.
- Received 8 April 1999
DOI:https://doi.org/10.1103/PhysRevE.61.R2196
©2000 American Physical Society