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Flow of wet granular materials

N. Huang·G. Ovarlez·F. Bertrand·S. Rodts·P. Coussot·Daniel Bonn
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Abstract

The transition from frictional to lubricated flow of a dense suspension of non-Brownian particles is studied. The pertinent parameter characterizing this transition is the Leighton number $Le = \frac{η_s \dotγ}σ$, which represents the ratio of lubrication to frictional forces. The Leighton number $Le$ defines a critical shear rate below which no steady flow without localization exists. In the frictional regime the shear flow is localized. The lubricated regime is not simply viscous: the ratio of shear to normal stresses remains constant, as in the frictional regime; moreover the velocity profile has a single universal form in both frictional and lubricated regimes. Finally, a discrepancy between local and global measurements of viscosity is identified, which suggests inhomogeneity of the material under flow.

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N. Huang, G. Ovarlez, F. Bertrand, S. Rodts, P. Coussot, Daniel Bonn. 2004-12-13. Flow of wet granular materials. https://doi.org/10.1103/physrevlett.94.028301

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