Experimental and theoretical studies of resonance effects during confined flow in silos

The paper deals with experimental and theoretical research of resonance effects during silo emptying. The influence of resonance effects on wall pressures in silos has been investigated with model tests and FE analyses. The model tests were carried out with a cylindrical and rectangular silo containing various cohesive and non-cohesive bulk solids. The onset of dynamic silo flow was simulated with controlled outlet velocity along the bottom in a plane strain model and large silo. The confined flow of dry sand in a silo with parallel walls during resonance was described with a finite element method based on a polar elasto-plastic constitutive law. It differs from the conventional theory of plasticity by the presence of Cosserat rotations and couple stresses using mean grain diameter as a characteristic length. In the FE calculations, the silo walls were taken into account.