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Phys. Rev. E 75, 032301 (2007) [4 pages]

Behavior of flowing granular materials under variable g

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Antje Brucks1,*, Tim Arndt1, Julio M. Ottino2,3, and Richard M. Lueptow3,†
1Zentrum für Angewandte Raumfahrttechnologie und Mikrogravitation (ZARM), Universität Bremen, Am Fallturm, 28359 Bremen, Germany
2Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
3Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA

Received 18 August 2006; revised 26 January 2007; published 28 March 2007

We consider the impact of the effective gravitational acceleration geff on gravity-driven granular shear flow utilizing a tumbler of radius R rotating at angular velocity ω when geff is varied up to 25 times the gravitational level on Earth in a large centrifuge. The Froude number Fr=ω2Rgeff is shown to be the proper scaling to characterize the effect of gravity on the angle of repose of the flowing layer. Likewise, transitions between flow regimes depend on Fr. Furthermore, the thickness of the flowing layer is independent of the g level. These results provide a starting point for understanding granular flows on planetary bodies with geff different than on Earth for application to planetary exploration and formation of geologic features.

© 2007 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevE.75.032301
DOI:
10.1103/PhysRevE.75.032301
PACS:
45.70.−n, 47.57.Gc

*Corresponding author. Electronic address: abrucks@uni-bremen.de

Corresponding author. Electronic address: r-lueptow@northwestern.edu