Experimental and theoretical investigations of silo music

Simulation of silo filling and discharge using ANSYS and comparison with experimental data

“…The Finite Element Method is a suitable technique to determine the stresses and displacements appeared on the walls or the bulk solid both for filling and discharge of the silo (Ooi and Rotter, 1990;Briassoulis, 2000;Gallego et al, 2010), or to analyze phenomena such as buckling (Iwicki et al, 2011), silo quaking (Wensrich, 2002), silo honking (Wilde et al, 2010), bursting (Piskoty et al, 2005), geometric imperfections (Teng et al, 2005) or eccentric hoppers (Guaita et al, 2003;Vidal et al, 2006). The Discrete Element Method is also increasingly being used for analyzing silos because it allows simulating the individual particles stored in the silo (Kobyłka and Molenda, 2014;Mellmann et al, 2014;Parafiniuk et al, 2013;González-Montellano et al, 2012).…”

High-speed imaging of traveling waves in a granular material during silo discharge

“…When a granular material is slowly discharged from a vertically aligned container (tube) one often observes vibrations accompanied by a booming low frequency (typically 50 − 200 Hz) sound. This phenomenon can be observed in large silos and is often referred to as silo music or silo honking, but it can also easily be reproduced in smaller scale laboratory experiments [1][2][3][4][5][6][7][8]. Silo quaking can also be observed during discharge [9,10] where short sharp bursts of motion are separated by longer periods of no movement.…”

“…Although resonances during silo discharge are long known in industry and have recently been investigated thoroughly [1][2][3][4], the phenomenon is not yet fully understood. While one explanation is based on stick-slip motion of the grains near the silo walls [4][5][6], other authors argue that the phenomenon originates from a dynamic interaction between the silo structure and the flowing material, where the source of the vibration is the transition zone between cylindrical and converging flow in the lower part of the system near the outlet [1][2][3]. Recent laboratory experiments carefully investigated the frequency spectrum of the vibrations by piezoelectric accelerometers and microphones [1][2][3][4][5] and related these observations of the calculated eigenfrequencies of the silo structure [3] and the time evolution of the density of the material detected by a non-invasive method (Electrical Capacitance Tomography) [1,2].…”

Visualisation of Granular Material Concentration Changes, During Silo Discharging Process, Using ECT Large Scale Sensor

“…Electrical Capacitance Tomography (ECT), which is the modality employed for measurements presented in this paper, is used for solid flow measurements in pneumatic conveying [4,5,6,7], gravitational flow in silos [8,9,10,11,12,13] or fluidized beds [14,15,16,17].…”