| Although the transport of bulk solids materials is an integral part of many industrial processes, the effect of microstructure formation, on the flow of granular material is not fully understood. In this work a particle dynamic computer simulation is used to investigate how microstructure affects the flow properties of grains in simple shear and gravity flow in a channel. The simulation used for this study is an event driven algorithm and simulations of large systems for long times have been performed due to the fact that the dynamics of large systems are often quantitatively and qualitatively different from those of small systems.; In this work, by varying the parameters of the system, the effect of clustering has been examined for simply sheared systems of inelastic disks and spheres. It was found that the long time average stresses and granular temperature initially increased with the system size and then approached limiting values as the size of the system was further increased. It was also observed that the distribution of stresses initially broadened with system size and then approached limiting distributions as the size of the system was further increased. Combining the values of the stresses obtained from our simulations with a previous theory for the clustering length scale, it has been determined that once clusters are fully formed in a system, the stresses no longer increase. These results suggest that under certain circumstances a small system can capture the overall behavior of a much larger system.; During rapid gravity-driven flow of granular material in a channel, three distinct forms of microstructure (a plug flow, sinusoidal waves and a clumped flow) are identified. The parameters of the system, which are shown to affect structure, include average solids fraction, coefficient of restitution, particle size, the size of the periodic cell, and the distance between confining walls. Local and global steady flow properties of the system, such as velocity, mass flux, granular temperature and stresses are also examined. Finally, the types of microstructure observed by our simulations are compared to those that are predicted using a linear stability analysis of equations of motion of rapid granular flow and good agreement is found. |
