Silo music — Mechanism of dynamic flow and structure interaction

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

“…Homogeneous phantom was located inside big scale ECT sensor space ( The image reconstruction process was conducted using prepared triangular mesh (Fig. 6(a)) with 704 elements - Results confirm the known effect presented in previous study of gravitational flow behaviour of granular material [7,8,9,10,26,27,28,29], which structure in the case of dense packing is loosened during flow. The level …”

Determination of bulk solid concentration changes during granular flow in a model silo with ECT sensors

“…In the second case, the raining procedure by means of a sieve located above the silo top was used. Tests were performed for gravitational outflow with a diameter of the symmetric outlet d 0 = 0.07 m. Strong dynamic effects accompanied by a booming sound (called silo music) due to a dynamic interaction between the solid and silo structure occurred in the upper part of the silo from the beginning of the silo discharge during mass flow (Gudehus and Tejchman, 1993;Tejchman, 1998;Wilde et al, 2008). The dynamic effects disappeared in the lower part of the silo when funnel flow took place.…”

“…The mass flow changes into funnel flow approximately in the middle of the silo height (about 0.85-1.0 m above the outlet). Since the phenomenon of the silo music did not depend on the outlet size and outlet location, the experiments were carried out only with the symmetric outlet of d 0 = 0.07 m. A mechanism of the origin of silo music was proposed in Wilde et al (2008). A similar phenomenon occurs also in large aluminum silos with the ratio of the height to diameter of 4-6 (Tejchman, 1999).…”

Description of the silo flow and bulk solid pulsation detection using ECT

“…10-13) show results for gravitational flow in smooth wall silo with sieve aided fill up in order to force the dense packing of sand particles before the discharging process. Such conditions cause the pulsations in sand behavior [5,6,22].…”

“…Moreover, silo music is not definitely well understood [5][6][7]. The causes of such behavior during gravitational flow are seek in the tendency for interaction between the movement of the granular material and the structure, stress fluctuation in the silo lower (hopper) section, rapid acceleration and deceleration in upper (bin) section.…”