A numerical study on orientational arrest and size segregation of dense particle flows using discrete element modeling

Sammanfattning: The thesis focuses on studying dense particle flows, which are either dry or submerged in a Newtonian fluid through two dimensional numerical simulations using the discrete element method (DEM). The First paper deals with dense suspensions in viscous regime under oscillatory planar shear. We found that having an oscillatory shear can help reducing the viscosity of the suspension. Also, in the frictional case oscillation can increase the suspension’s shear jamming packing fraction. Furthermore, at small oscillatory strains, frictionless ellipses become dynamically arrested in their initial orientational configuration. In the second paper, we studied size segregation in a bi-disperse mixture of big and small discs. We applied an iterative force measurement technique to find the restoring/segregation force on big and small particles in the system when we have constant or linearly increasing vertical gravity. Our method works equivalently well as a previously introduced method for the case of having a constant vertical gravitational field while it can find the restoring force for the case of linearly increasing gravity whereas the other method fails to measure the force.