SILO-MUSIC AND SILO-QUAKE EXPERIMENTS AND A NUMERICAL COSSERAT APPROACH

During silo emptying dynamical effects, viz. vibrations (called silo music) and shocks (called silo quake) come into being in a silo fill. Model and full-scale experiments were carried out to investigate these dynamical phenomena. Model tests were performed with a slender perspex cylinder. Silo music was observed with a dry sand, and silo quake was registered with a weakly cohesive sand. Full-scale tests were carried out in a silo in Poland filled with rape seeds. Pronounced pulsations during silo emptying were registered. Experiments with a dry sand were modelled with a finite element method, with consideration of inertial forces, on the basis of an elasto-plastic Cosserat type theory following Muhlhaus. Calculations were performed for a velocity controlled mass flow and a free outflow. Comparison between the numerical calculations and the experimental results shows rather satisfactory agreement.