Exploring Correlations Between Spatially Heterogeneous Dynamics and Clogging Behavior in a Quasi-2D Granular Silo

Abstract

Jamming is a phenomenon in granular systems that is similar to a thermodynamic phase transition, like freezing. With jamming, a system shifts from liquid like behavior to solid-like behavior. In phase transitions other features are observed, such as increased fluctuations near the transition point. In jamming transitions, this has been observed as spatially heterogeneous dynamics (SHDs) increasing near the transition [24, 32]. In this work, we investigate whether SHDs occur in granular systems approaching the clogging transition, a transition distinct from jamming. We apply techniques to measure SHDs successfully implemented for jammed systems, such as strings, χ4, and grain boundaries [32, 36]. Due to the localized nature of clogging, we have focused our are of interest on the more immediate are around the aperture of a system. We examined experimental data collected by Harada (MHC ‘18) in quasi 2D granular silos. With this data we used tracking code that implements the Crocker-Grier method [18, 38], to identify and track particles from frame to frame. With this position data, we are able to identify the crystallinity of the packing throughout our systems. Our goal was to find specially heterogenous dynamics in these systems by finding the amount of disorder in the particle packing of these systems. In addition to this, we compared the trends in the amount of disorder of systems that clogged and systems that did not clog, as well as systems with and without obstacles. We found that an overall higher level of disorder in a system could be correlated to a larger amount of mobility in the system, similar to granular temperature [18].

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