Journal of Fluid Mechanics

Papers

Experimental investigation and kinetic-theory-based model of a rapid granular shear flow

R. D. WILDMANa1, T. W. MARTINa1, J. M. HUNTLEYa1, J. T. JENKINSa2, H. VISWANATHANa1, X. FENa3 and D. J. PARKERa3

a1 School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, UK

a2 Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853 USA

a3 School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK

Abstract

An experimental investigation of an idealized rapidly sheared granular flow was performed to test the predictions of a model based on the kinetic theory of dry granular media. Glass ballotini beads were placed in an annular shear cell and the lower boundary rotated to induce a shearing motion in the bed. A single particle was tracked using the positron emission particle tracking (PEPT) technique, a method that determines the location of a particle through the triangulation of gamma photons emitted by a radioactive tracer particle. The packing fraction and velocity fields within the three-dimensional flow were measured and compared to the predictions of a model developed using the conservation and balance equations applicable to dissipative systems, and solved incorporating constitutive relations derived from kinetic theory. The comparison showed that kinetic theory is able to capture the general features of a rapid shear flow reasonably well over a wide range of shear rates and confining pressures.

(Received October 10 2006)

(Revised January 17 2007)

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