Model tests of silo discharge in a geotechnical centrifuge

Abstract

Scaled models are often used to study the behaviour of silo discharge, however the effects of gravity on silo discharge have not yet been quantified. In this paper, the effects of gravity on silo discharge and internal flow patterns are investigated with reference to the widely used Beverloo correlation. Discharge rate is predicted to be proportional to the square root of gravity and this is demonstrated using experimental results from a novel silo centrifuge model. The effects of changes in gravity on the internal flow profile are also investigated. It is shown that the width of the flow channel at any given height above the outlet is independent of gravity and the local velocity of discharging material is proportional to the square root of gravitational acceleration. These observations show that the angle at which a stagnant zone intercepts a silo wall is independent of gravity and that the criteria for funnel or mass flow conditions are independent of gravity.