title: Dynamics of self-assembled chaining in magnetorheological fluids.
abstract: The aggregation dynamics of paramagnetic spherical particles embedded in a viscous fluid is investigated via numerical simulations using a fully coupled three-dimensional model. Particles experience simultaneously Brownian motion, dipolar magnetic attraction, and multibody hydrodynamic interactions. When the dipole strength characterizing the ratio of magnetic attraction to random diffusion exceeds a critical value, particles join together forming supraparticle structures. As time evolves, particle/chain and chain/ chain interactions lead to a continuous increase of the cluster size. The mean length of particle chains has a power-law dependence with respect to time, as predicted by the theory of diffusion-limited aggregation. Both the exponent and the characteristic time scale agree very well with the experimental results of Promislow et al.
authors.affiliation: Center for Fluid Mechanics, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Climent
authors.forename: Martin R
authors.initials: MR
authors.lastname: Maxey
authors.forename: George Em
authors.initials: GE
authors.lastname: Karniadakis