Silo quakes

Sometimes there are problems with self-induced bin vibrations. If these vibrations are high in frequency but low in amplitude, an interesting phenomenon called silo music (humming) or sik) honking may be experienced. This can be a nuisance to personnel or neighbours nearby but is usually not a structmal concern. If, on the other hand, the bin vibrations are low in frequency but high in amplitude, the result is what are called silo quakes. These apply massive dynamic loads that most vessels are not designed to withstand. Structural failures have occurred due to this mechanism. 

Since many problems like silo quaking and others are initiated by non-uniform flow, the velocity fluctuations have to be investigated to determine their amplitude and frequency. This analysis leads to an assessment of the forces applied to the sUo due non-uniform flow. Therefore, at a specific point, the velocities are measured and analyzed over a period. The velocity fluctuations were found in fimnel-flow and mass-flow silos. The change in amplitude was more intense in the mass-flow silo. The reason for this is presumably due to the fact that in the mass-flow silo a larger amount of bulk solid is in motion. Therefore, the fluctuation are described in this paper for the mass-flow silo. The fluctuations are analyzed in the center at x = 0 mm and y = 600 mm. The measured time averaged velocity at this point was v = 0.175 ms (figure 2b). In figure 6a the velocity fluctuations are depicted for a period of 4 s. It can be seen that the amplitude of the velocity fluctuations reaches values of up to 40% of the mean velocity of 0.175 ms . Between t = 1 s and 2 s the number of fluctuations are much smaller than at the other times. 

B. Hardow, D. Schulze and J. Schwedes. An Experimental Analysis of the silo quaking phenomenon. In 3rd World Congress on Particle Technology, vol. 318. Brighton, UK, 1998. ... 

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See also in sourсe #XX -- [ ]

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