Simulations of behavior of magnetic particles in magnetic functional fluids using a hybrid method of lattice Boltzmann method, immersed boundary method and discrete particle method

•New hybrid code of LBM-IBM-DPM with magnetic interactions for MR fluids is developed.•Three-dimensional microstructures of magnetic particles in MR fluids are visualized•Microstructures in MR fluid flows are shown considering fluid-particle interactions.•Requirement of forming sheet-like structures of chain-like clusters is reported.

The microstructure formation of magnetic particles in magnetorheological (MR) fluids has an important role on the macroscopic properties such as viscosity. To simulate the behavior and microstructure formation of magnetic particles, hybrid simulations were conducted by combining the lattice Boltzmann, immersed boundary and discrete particle methods, and by taking account of magnetic interactions between magnetic particles under an external magnetic field. The microstructure formation of magnetic particles in an MR fluid between two parallel plates, where one plate moves with constant velocity and the plate remains stationary, is calculated. A sheet-like structure appears when relatively strong shear and strong magnetic field are applied. In contrast, a fibrous-like structure moves in the flow when the shear is small.