s1-ln16404694-153404319-1939656818Hwf403821386IdV-29133194516404694PDF_HI0001.pdf (7.84 MB)

Nuclear magnetic resonance measurements of velocity distributions in an ultrasonically vibrated granular bed

Download (7.84 MB)
journal contribution
posted on 26.04.2016, 09:03 by Jonathan Huntley, Tahir Tarvaz, M.D. Mantle, A.J. Sederman, L.F. Gladden, Nadeem A. Sheikh, Ricky D. Wildman
We report the results of nuclear magnetic resonance (NMR) imaging experiments on granular beds of mustard grains fluidised by vertical vibration at ultrasonic frequencies. The variation of both granular temperature and packing fraction with height was measured within the three-dimensional cell for a range of vibration frequencies, amplitudes and numbers of grains. Small increases in vibration frequency were found – contrary to the predictions of classical ‘hard-sphere’ expressions for the energy flux through a vibrating boundary – to result in dramatic reductions in granular temperature. Numerical simulations of the grain-wall interactions, using experimentally-determined Hertzian contact stiffness coefficients, showed that energy flux drops significantly as the vibration period approaches the grain-wall contact time. The experiments thus demonstrate the need for new models for ‘soft-sphere’ boundary conditions at ultrasonic frequencies.

Funding

This paper was supported by funding under Platform Grant EP/F047991/1

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES

Volume

372

Issue

2015

Pages

? - ? (17)

Citation

HUNTLEY, J.M. ...et al., 2014. Nuclear magnetic resonance measurements of velocity distributions in an ultrasonically vibrated granular bed. Philosophical Transactions of The Royal Society A-Mathematical Physical and Engineering Sciences, 372: 20130185.

Publisher

© The Authors. Published by The Royal Society

Version

AM (Accepted Manuscript)

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

2014-05-13

Notes

This paper was accepted for publication in the journal Philosophical Transactions of The Royal Society A-Mathematical Physical and Engineering Sciences and the definitive published version is available at http://dx.doi.org/10.1098/rsta.2013.0185

ISSN

1364-503X

Language

en