Computations of granular flow and pressures in a flat-bottomed silo

The most demanding design situations for silo structures usually occur at t he onset of discharge, when the silo is still almost full of granular solid . In this condition, the pattern of solids flow affects the wall pressures, and both are currently difficult to predict even using the best numerical models. This paper describes part of an international collaborative study i n which finite element and discrete element models were used by many leadin g research groups around the world to model a single well-defined problem o f discharge from a flat-bottomed silo using many different programs. The re sults show that discrete element models give good qualitative predictions o f flow patterns, and the finite-element models give good quantitative predi ctions of pressure regimes, but there is little agreement on the details ei ther within each modeling paradigm or between them. Further extensive resea rch is needed to reach a scientific consensus on the requirements for a rel iable formulation.