Bidimensional flow behaviour of granular material

In this paper a new approach to velocity fields of granular materials with the fluid constitutive law is presented using a part of the application of the kinetic grain flow model proposed by [ Haff, 1983 ] . The shape of the particles constituting the material is supposed spherical with a perfectly smooth surfaces preventing rotation couples for the grains during binary collisions of short duration. In some hypotheses for boundary conditions and for horizontal component velocity, the equation of motion is reduced to an ordinary differential equation for the fluctuation velocity ν (microscopic value). This differential equation is solved numerically including optimisation of the material parameters. Experiments were set up in an attempt to generate two-dimensional flow coresponding to this analyses. Several experimental velocity profiles are measured with walls varying in roughness. The numerical results obtained correspond to experimental measurements using peas and glass beads [WEISSE, 1991].