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arXiv · 2003.06102

Clogging in bidirectional suspension flow

Emily A. Hobbs·Alexander Christensen·Brian C. Utter
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Abstract

The sudden arrest of motion due to confinement is commonly observed via the clogging transition in the flow of particles through a constriction. We present results of a simple experiment to elucidate a similar transition in the bidirectional flow of two species in which two species of macroscopic particles with different densities are confined in a tube and suspended in a fluid of intermediate density. Counterflowing grains serve as mobile obstacles and clogging occurs without arch formation due to confinement. We measure the clogging or jamming probability $J$ as a function of number of particles of each species $N$ in a fixed channel length for channel widths $D = $ 3$-$7$d$, where $d$ is the particle diameter. $J(N)$ exhibits a sigmoidal dependence and collapses on a single curve $J(N/D^3)$ indicating the transition occurs at a critical density. Data is well-fit by a probabilistic model motivated by prior constriction flows which assumes grains enter the clogging region with a fixed probability to produce a clogging state. A quasi-two-dimensional experiment provides insight into the interface shape and and we identify a Rayleigh-Taylor instability at large channel widths.

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Emily A. Hobbs, Alexander Christensen, Brian C. Utter. 2020-03-13. Clogging in bidirectional suspension flow. https://arxiv.org/abs/2003.06102

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