A granular material flow is a form of two-phase flow consisting of particulates and an interstitial fluid. When sheared the particulates may either flow in a manner similar to a fluid, or resist the shearing like a solid. The dual nature of these types of flows makes them very difficult to analyze.
Many examples of granular flows can be found in both industry and nature. Hoppers, chutes, and conveyor belts are used when transporting particulate materials such as food stuffs, pharmaceuticals, and coal. Fluidized bed reactors are commonly used for chemical reactions involving a solid and a liquid (or gas). Other industrial applications include packing of granular materials, particulate segregation and mixing, and particulate drying. In nature, examples of granular flows include avalanches, river sedimentation, dune formation, planetary ring dynamics, soil liquifaction, and ice flow mechanics. Clearly, understanding the behavior of granular materials will provide useful information.
