Influence of hydrodynamic drag model on shear stress in the simulation of magnetorheological fluids

• Magnetorheological fluids are modeled with the DEM–SPH method for the first time.
• The viscosity as a function of Mason number is in good agreement with experiments.
• Different drag models are systematically compared.
• The analysis of the stress contributions reveals the origin of stress differences.
• A criterion for the validity of the DEM-Stokes drag model is derived and tested.

Simulations of magnetorheological fluids are performed with different models for the hydrodynamic drag law. The shear stress predictions from two coupled discrete element – smoothed particle hydrodynamics models with different drag laws are compared to pure discrete element simulations for a wide range of Mason numbers. The discrete element model has a higher computational efficiency but the treatment of the hydrodynamic drag force involves some rough approximations. Based on the results of this study, a criterion is proposed for the applicability of the pure discrete element model in the simulation of sheared magnetorheological suspensions.