Magnetic-Induced Migration in a Sedimenting Suspension of Magnetic Spherical Particles

Abstract

We study the relative trajectories of two magnetic spheres interacting in a dilute suspension in the presence of particle inertia and Brownian motion effect. The particles settle relative to one another under the action of gravity and when in close contact they exert on each other a magnetic force and torque due to a permanent magnetization. The balance equations of forces and torques for the two particles are considered in the present formulation. The numerical simulations are based on direct computations of the hydrodynamic and the magnetic interactions among the rigid spheres in the regime of no-null Stokes number. The behavior of these suspensions is examined based on the relative trajectories calculated for several initial configurations. The calculations show that fluctuations in particle orientation produced by the continuous magnetic interactions and by the Brownian motion exerts a significant effect on the understanding of particle aggregation and particle migration in magnetic suspensions.