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DY: Fachverband Dynamik und Statistische Physik

DY 1: Focus Session: Dense Granular Flow

DY 1.1: Invited Talk

Monday, March 14, 2011, 10:15–10:45, HÜL 186

Dense Inclined Flows of Granular Materials — •James Jenkins — Cornell University, Ithaca, NY, USA

Hydrodynamic equations that result from classical kinetic theory, modified to incorporated energy lost in collisions, have been applied with success to dilute and moderately dense collisional granular flows. However, for inclined flows of identical sphere with concentrations above 49 per cent, their predictions do not agree with what is seen in numerical simulations and physical experiments. In this talk, we present a slightly modified hydrodynamic theory for inelastic spheres. The modification is the introduction of a length other than the diameter in the expression for the rate of collisional dissipation. This length is determined by a simple algebraic balance between the creation and destruction of particle chains. We apply the theory to dense collisional flows down both erodible and rigid, bumpy inclines and determine profiles of particle concentration, mean velocity, and fluctuation energy for steady, fully-developed flows of identical, frictional spheres. The profiles exhibit the features seen in the numerical simulations, and the integration of the energy balance through the depth of the flow results in an improvement of a velocity scaling employed in the interpretation of the physical experiments.