Segregation of charged particles under shear
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We study segregation of a binary mixture of differently charged particles under shear using particle-based simulations. We simulate particle dynamics using a discrete-element model including electrostatic interactions and find that particles segregate according to their net charge. Particles that are charged twice as strong as other particles of the same electrical sign are seen more at insulating boundaries with which we shear the system. Weakly charged particles, on the other hand, stay more in the center of the sheared bed. To understand this segregation, we propose a simple model based on electrostatic potential energy, which shows that the segregated system we observe in our simulations is indeed the most favorable configuration. Our simulations further show that for a given packing fraction and a given simulation time there is an optimal shear velocity where the segregation is maximal. We show that this maximum results from a competition between diffusional and Coulomb fluxes. For a larger shear velocity, diffusion suppresses segregation as proportional to the fluctuation velocity.
KeywordsParticle segregation Shear flow Electrostatics Discrete element method simulations
We acknowledge financial support from the European Research Council (ERC) Advanced Grant 319968-FlowCCS and the INCT-SC. NA acknowledges financial support from the Portuguese Foundation for Science and Technology (FCT) under Contract No. UID/FIS/00618/2013, and from the Luso-American Development Foundation (FLAD), FLAD/NSF, Proj. 273/2016. TS acknowledges support from the NSF DMR, award \(\sharp \)1404792.
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Conflict of interest
The authors declare that they have no conflict of interest.
Supplementary material 1 (mov 3548 KB)
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