Rheology of a dilute ferrofluid droplet suspension in shear flow: Viscosity and normal stress differences

Abstract

The rheology of a dilute ferrofluid droplet suspension under simple shear flow is studied using three-dimensional lattice-Boltzmann simulations and the phase-field model. By changing the external field strength and direction, it is found that the suspension rheologies (viscosity and normal stress differences) can be drastically modified. For example, by imposing an external magnetic field, the specific viscosity becomes 12-620% of that under no external field. This suggests that a ferrofluid droplet would be a practical complex fluid for controlling suspension properties, just by changing the external magnetic field strength and direction.