Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy
1 School of Chemical Engineering and Advanced Materials, Newcastle University, NE1 7RU, United Kingdom
2 a. School of Optical-Electrical and Computer Engineering, b. school of medical instrument and food engineering, c. Shanghai Key Lab of Modern Optical System, d. Engineering Research Center of Optical Instrument and System, Ministry of Education, University of Shanghai for Science and Technology, Shanghai, 200093, China
3 School of Science, Loughborough University, LE11 3TU, United Kingdom
* Corresponding author: email@example.com
Published online: 30 June 2017
Granular materials in rotating drums are of wide interest not only because of their extensive use in the industrial contexts, but also as model systems in the study of natural disasters, such as avalanches or landslides. Most of available experimental methods are restricted to surface layer flows and dilute systems whilst the remainder can only resolve the granular dynamics to a fine scale with relatively poor temporal resolution or vice versa. In contrast, speckle visibility spectroscopy (SVS) is able to resolve the average of the three components of motion of grains in dense systems in small volume of granular media several layer deep with spatio-temporal resolutions that allow the probing of the granular micro-dynamics. We have used this technique to study granular dynamics of surface avalanche flow in the slumping regime using both spherical glass and irregular sand particles. Although results are very similar, we determined that visually observed compaction at the beginning of avalanche process for irregular sand particles influence time evolution of the particle fluctuation velocity during avalanches.
© The Authors, published by EDP Sciences, 2017
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