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Related Experiment Video

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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

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Published on: December 4, 2017

Crossover transition in flowing granular chains.

Xialing Ulrich¹, Eliot Fried, Amy Q Shen

¹Department of Mechanical, Aerospace & Structural Engineering, Washington University in St Louis, Missouri 63130, USA.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|November 13, 2009

Summary

Granular chains in a rotating tumbler exhibit complex dynamics, forming mixed packing structures. Chain length influences their movement, transitioning from self-avoiding to random walks as they grow.

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Area of Science:

Physics of granular materials
Soft matter physics
Complex systems dynamics

Background:

Understanding the behavior of granular materials is crucial in various scientific and industrial applications.
Flowing granular chains exhibit unique dynamical and statistical properties influenced by confinement and chain length.

Purpose of the Study:

To investigate the dynamical and statistical behavior of two-dimensional granular chains in a rotating tumbler.
To characterize the influence of chain length on system conformation and flow dynamics.

Main Methods:

Experimental study using a rotating tumbler to confine granular chains in two dimensions.
Analysis of chain dynamics, including cascades and packing arrangements.
Measurement of system porosity and mean-square end-to-end distance.

Main Results:

Observed cascades of chains along the free surface, leading to mixed porous/laminar packing.
Identified crossover transitions in chain conformation from 2D self-avoiding walk to 2D random walk.
These transitions are dependent on chain length, specifically when self-contact becomes possible.

Conclusions:

The length of granular chains significantly impacts their dynamical and statistical behavior in confined flow.
Chain conformation transitions are a key indicator of how chain length affects packing and flow in granular systems.