Fluid-particle and granular flows exhibit rather complex behavior, for
example, the occurrence of bubbles and clusters in gas-particle flows,
and clogging and size segregation in granular flows. This work is to
advance our understanding of granular and gas particle flows using
computational simulations. In gas-particle fluidized beds, confined
between parallel solid walls, non-uniform solids distribution is
observed and the flow profiles are strongly related to the physical and
operating parameters, such as particle inelasticity, gravity, bed width
and mean solids fraction. A stability analysis has been carried out to
investigate the instabilities in gas-particle flows and the generation
of cluster, bubbles or streamers in gas-fluidized beds. For boundary
driven and body-force-driven granular flows and gas-particle fluidized
beds with polydisperse particle mixtures, the particle species
segregation is enhanced with a decrease in the system elasticity, an
increase in the average solids fraction or an increase in the size
ratio, due to the competition of diffusion forces. The distribution of
granular energy and its effect on the segregation is also considered in
this work.