Dynamics of magnetic chains in a shear flow under the influence of a uniform magnetic field

Abstract

Travelling waves in a cylindrical magnetohydrodynamically forced flow Phys. Fluids 24, 044101 (2012) Two-dimensional numerical analysis of electroconvection in a dielectric liquid subjected to strong unipolar injection Phys. Fluids 24, 037102 (2012) We numerically investigate dynamics of magnetic chains and flow characteristics in a two-dimensional shear flow under the influence of a magnetic field applied externally. A direct simulation method is employed to solve the particulate flow in the creeping flow regime, taking into account both magnetic and hydrodynamic interactions in a coupled manner. In a periodic channel, the dynamics of chains is found to be significantly influenced by the Mason number (the ratio of viscous force to magnetic force), the magnetic susceptibility, and the particle fraction. Below a critical Mason number, a chain rotates and reaches an equilibrium. Above the critical value, however, the chain continuously rotates as a rigid body. Thinning behavior in the wall shear stress is found above a threshold value of the Mason number.

Magnetic interaction of Janus magnetic particles suspended in a viscous fluid

“…Compared with the method introduced in the previous studies [32,36,37], the major differences are in the treatment of the magnetic anisotropy of the particles dependent on their orientations and the use of the modified rigid-ring description implemented by means of Lagrange multipliers. Introduced below are the weak forms to solve the two-dimensional magnetic particulate flow with circular Janus magnetic particles.…”

“…Even though modeling and simulation are employed to investigate the self-assembly and the dynamics of Janus particles [26][27][28][29][30][31], further studies are still required to understand the magnetic interaction lying behind the formation of various self-assembly structures and the fluid flow induced by the actuated particles. Direct numerical simulation schemes [32][33][34][35][36][37], which have been developed to solve particulate flows with isotropic magnetic particles, are promising options in tackling particulate flows with Janus magnetic particles if they are enhanced to take into account the magnetic anisotropy of the particles.…”

“…In this study, a previously developed two-dimensional numerical scheme [36] is enhanced to treat the magnetic anisotropy of the particles. To the best of our knowledge, this is the first attempt to apply the direct simulation scheme to solve particulate flows with suspended Janus magnetic particles.…”

The Role of Volume Fraction and Additives on the Rheology of Suspensions of Micron Sized Iron Particles

“…In fact, almost all numerical simulations of MR suspensions use the dipolar approximation, which largely underestimates the magnetic force (Clercx and Bossis, 1993). We have found one paper (Lacis and Gosko, 2009) using an expression similar to Equation (1), with some tables derived from FEM simulations for two particles and another based on FEM simulations between several particles in a single chain (Kang et al, 2012). A simulation method, called smooth particle dynamics (Hashemi et al, 2016(Hashemi et al, , 2018, can also be used to solve the magnetostatics equation between several particles, but is restricted to a few particles with a rather small (<10) susceptibility.…”

A study on laminated structures in Terfenol-D/Epoxy particulate composite with enhanced magnetostriction

“…Similar chain structures were also observed and modeled in magnetorheological fluid. [13][14][15] In this paper, we discovered a laminated structure in Terfenol-D/Epoxy particulate composite after dynamic orientation, where an oscillating magnetic field was applied along the cylindrical axis instead of a static one. Terfenol-D particles were found to aggregate in several planes to form parallel layers in the matrix phase.…”