Dynamical states of bubbling in vertically vibrated granular materials. Part I: Collective processes

Granular materials deform plastically like a solid under weak shear and they flow like a fluid under high shear. These materials exhibit other unusual kinds of behavior, including pattern formation in shaking of granular materials for which the onset characteristics of the various patterns are not well understood. Vertically shaken granular materials undergo a transition to a convective motion which can result in the formation of bubbles. In Part I, a detailed overview is presented of collective processes in gas-particle flows useful for developing a simplified model for molecular dynamic type simulations of dense gas-particle flows. The large eddy simulation method (LES) has been employed for simulating fluid flows through irregular array of particles. The results obtained may lead to scale-dependent closures for quantities such as the drag, stresses and effective dispersion. These are of use for developing a continuum approach for describing the deformation and flow of dense gas-particle mixtures described in Part II.