Lubrication effects on the flow of wet granular materials

Abstract

We investigate the dynamics of a partially saturated grain-liquid mixture with a rotating drum apparatus. The drum is partially filled with the mixture and then rotated about its horizontal axis. We focus on the continous avalanching regime and measure the impact of volume fraction and viscosity of the liquid on the dynamic surface angle. The inclination angle of the surface is observed to increase sharply to a peak and then decrease as a function of liquid volume fraction. The height of the peak is observed to increase with rotation rate. For higher liquid volume fractions, the inclination angle of the surface can decrease with viscosity before increasing. The viscosity where the minima occurs decreases with the rotation rate of the drum. Limited measurements of the flow depth were made, and these were observed to show only fractional changes with volume fraction and rotation speeds. We show that the qualitative features of our observations can be understood by analyzing the effect of lubrication forces on the timescale over which particles come in contact.

arXiv comment7 pages, 8 figures

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• Wet Granular Materials
• How Sandcastles Fall
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• Maximum Angle of Stability of a Wet Granular Pile
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• Plug flow and the breakdown of Bagnold scaling in cohesive granular flows
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Cited by in corpus (6)

• Wet granular flow control through liquid induced cohesion
• Collapse of quasi-two-dimensional wet granular columns
• Simple Model for Wet Granular Materials with Liquid Clusters
• Compaction dynamics of a magnetized powder
• Structural similarity between dry and wet sphere packings
• Reorganization of a granular medium around a localized transformation