Abstract
We study experimentally the flow and patterning of a granular suspension displaced by air inside a narrow tube. The invading air-liquid interface accumulates a plug of granular material that clogs the tube due to friction with the confining walls. The gas percolates through the static plug once the gas pressure exceeds the pore capillary entry pressure of the packed grains, and a moving accumulation front is reestablished at the far side of the plug. The process repeats, such that the advancing interface leaves a trail of plugs in its wake. Further, we show that the system undergoes a fluidization transition—and complete evacuation of the granular suspension—when the liquid withdrawal rate increases beyond a critical value. An analytical model of the stability condition for the granular accumulation predicts the flow regime.
- Received 10 March 2016
DOI:https://doi.org/10.1103/PhysRevLett.117.028002
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Forming Granular Plugs
Published 7 July 2016
Experiments on grain-water-air mixtures flowing through a tube find that frictional forces between the grains and the tube lead to the creation of a series of plugs.
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