Microstructure dynamics in shear thickening suspensions

Dense suspensions of hard particles display a characteristic increase in viscosity when sheared. This behavior depends on the rate of shear imposed, and has puzzled scientists for decades. Spurred by recent advancements in experimental, theoretical and simulation results, the field is coming to a consensus that frictional contacts between particles in suspensions play a major role in the shear thickening process. Microscale parameters like particle shape, friction coefficient, size ratios and polydispersity have been observed to have significant impact on the macro scale rheology. Using detailed models containing Lagrangian particles immersed in a Lattice Boltzmann Method based fluid, we simulate shear thickening and tune these parameters in order to understand the role of particle interactions and the resultant microstructures of particles that form within the suspensions. This thesis contains works that focuses on the pertinent questions about phenomena in the micro and macro scales that occur during shear thickening, under the influence of these microscale parameters.