https://doi.org/10.1051/epjconf/201714010009
Slip-stick excitation and travelling waves excite silo honking
1 University of Cambridge, UK, Department of Applied Mathematics and Theoretical Physics
2 Imperial College London, UK, Department of Mechanical Engineering
3 University of Twente, Netherlands, Department of Mechanical Engineering
* e-mail: n.m.vriend@damtp.cam.ac.uk
Published online: 30 June 2017
Silo honking is the harmonic sound generated by the discharge of a silo filled with a granular material. In industrial storage silos, the acoustic emission during discharge of PET-particles forms a nuisance for the environment and may ultimately result in structural failure. This work investigates the phenomenon experimentally using a laboratory-scale silo, and successfully correlates the frequency of the emitted sound with the periodicity of the mechanical motion of the grains. The key driver is the slip-stick interaction between the wall and the particles, characterized as a wave moving upwards through the silo. A quantitative correlation is established for the first time between the frequency of the sound, measured with an electret microphone, and the slip-frequency, measured with a high-speed camera. In the lower regions of the tube, both the slip-stick motion and the honking sound disappear.
© The Authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
