Flow of granular material through a plane hopper

Abstract

This paper presents some experimental results of an investigation of flow patterns of sand in a plane, wedge-shaped hopper model and also an approach to a theoretical description of the discharge process. A non-steady discontinuos velocity field was observed in the experiments. Velocity discontinuities were traced during the process of discharge using the stereophotographic technique. Complementary information about the density variations of the material during discharge was obtained from X-ray pictures and from ultrasonic measurements. Theoretical description of the velocity field is restricted to the advanced flow, which, as demonstrated in the experiments, can be treated approximately as a pseudo-steady process. An approach based upon the plane plastic flow theory of incompressible Coulomb material is applied. The theoretical solution for the velocity field is compared with some of the experimental results.