Random Close Packing of Disks and Spheres in Confined Geometries

ORAL

Abstract

We study the structure of many simulated random closing packings confined between two walls. Each packing consists of a binary mixture in equal number with a sizes ratio of 1.4. Our aim is to quantify how a confining boundary and the thickness between the boundaries alters the structure of randomly close packed disks in 2D and spheres in 3D. We find that confinement lowers the packing fraction, and induces heterogeneity in particle density where particles show strong layering near the wall. Both the particle density and the structure of the local packing show oscillations that decay outward from the wall. The decay in the oscillations is rapid, with a characteristic length scale on the order of the largest particle diameter. We invoke a simple model to describe the decrease in packing fraction with confinement.

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Authors

  • Kenneth Desmond

    Emory University

  • Milind Purohit

    Univ of South Carolina, Benedict College, Sc 29204, Univ. South Carolina, Benedict College, Univ South Carolina, GA Tech, Central Microscopy Research Facility, University of Iowa, Iowa City, Iowa 52242, USA, Department of Chemistry, University of Sri Jayewardenepura, Nugegoda, Sri Lanka, Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, USA, Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294, Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, College of William \& Mary, Harvard University, Benedict College, SC 29204, Massachusetts Institute of Technology, University of Applied Science, Bielefeld, Germany, Francis Marion University, Physics Dept., Emory University, Emory University, Formerly Emory University, currently UCLA, Physics Department, Georgia State University, Univ. of Georgia, Dept. of Chemistry, Universidad Nacional de Quilmes, Argentina, Pr, Dr, Derpartment of Physics, Florida A\&M University, Tallahassee, FL-32307, Department of Physics, Emory University, Georgia Institute of Technology, Naval Research Laboratory, University of Alabama, Tsinghua University, Lawrence Berkeley National Laboratory, Vanderbilt University, Jagellonian Univ., Univ. of Bonn, North Carolina A\&T State Univ., North Carolina Central Univ., Duke Univ. and TUNL, Georgia State University, Dept of Physics, Emory University, Cell Biology Department, Emory University, Physics Department, Emory University, University of South Carolina