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Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy

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journal contribution
posted on 31.07.2015, 14:05 by H. Yang, R. Li, P. Kong, Q.C. Sun, Mark Biggs, Vladimir Zivkovic
We used speckle visibility spectroscopy to measure the time-resolved dynamcis of avalanching down the inclined surface of a granular material in a half-full rotating drum operating in the slumping regime. The distribution of the avalanche period, t d , rest time between them, t r , and peak particle velocity fluctuation, δv 2 p , are all normally distributed. While the distributions of the two times at the top and bottom of the free surface are very similar, the particle velocity fluctuation is greater at the bottom of the free surface than at the top. The rest time is observed to be inversely related to the drum speed. Combining this with the relation of t r and the difference of the upper and lower angle of repose for the granular material, Δθ , we find that the latter decreases linearly with increasing rotational speed. We also observe that t d increases in a linear fashion with the drum speed. Using the relation of t r and the distance that particles have to move during an avalanche, we further find that a new scaling relation of the mean number of avalanches required to traverse the free surface with drum speed. We find that the slumping frequency increases with the rotating speed before becoming constant in the slumping-to-rolling transition region. Finally, we find that the average peak of the fluctuation speed of the avalanche, δv 2 p , increases linearly with the drum speed.

Funding

This work has been supported by Innovation Program of Shanghai Municipal Education Commission (15ZZ072), the fund for young college teachers by Shanghai Municipal Education Commission (zzslg2040), Hujiang Foundation of China (C14002).

History

School

  • Science

Department

  • Chemistry

Published in

PHYSICAL REVIEW E

Volume

91

Issue

4

Pages

? - ? (8)

Citation

YANG, H. ... et al, 2015. Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy. Physical Review E, 91 (4), 042206.

Publisher

© American Physical Society

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2015

Notes

This article was published in the journal Physical Review E [© American Physical Society].

ISSN

1539-3755

Language

en

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