Shear dispersion in dense granular flows
  We formulate and solve a model problem of dispersion of dense granular materials in rapid shear flow down an incline. The effective dispersivity of the depth-averaged concentration of the dispersing powder is shown to vary as the P\'eclet number squared, as in classical Taylor--Aris dispersion of molecular solutes. An extensions to generic shear profiles is presented, and possible applications to industrial and geological granular flows are noted. 
Ivan C. Christov and Howard A. Stone
physics.flu-dyn cond-mat.soft