Current continuum models based on the theory of plasticity have failed to describe the observed gravitational flow patterns of granular particles in a confined geometry. We propose a random-walk model that correctly predicts the shape of the free surface of the granular media and the solid stream lines with and without obstacles. We present simulation results that qualitatively exhibit many of the unique features of granular flows. The simulation results are also compared with experimental data.

• Received 13 March 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.828