Numerical simulation of dry particulates: Microstructure and stress differences in shearing flows

Conference · Mon Oct 01 00:00:00 EDT 1990

OSTI ID:5185699

Walton, O R ^[1]; Drake, T G ^[2]; Rosato, A ^[3]

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1. Lawrence Livermore National Lab., CA (United States)
2. California Univ., Los Angeles, CA (United States). Dept. of Earth and Space Sciences
3. New Jersey Institue of Technology, Newark (United States). Mechanical Engineering

Steady shearing flows of smooth, highly inelastic spheres were studied using both rigid and slightly-deformable sphere molecular- dynamics-like computer simulation models. These studies confirmed the expected large first-normal stress differences in dilute flows, but also showed evidence of cluster-like structures at a solids fraction near 0.1 when using an extremely low coefficients of restitution. This cluster formation appears to be the cause of a cusp, at a packing fraction of 0.1, in the first normal stress difference vs. packing fraction curve for steady shearing assemblies of spheres with coefficients of restitution near zero (e.g., with e = 0.01). Aside from this anomaly the first and second normal stress differences agree qualitatively with recent (anisotropic velocity distribution) kinetic theory predictions (Richman, J. Rheology, 33(8), 1293 (1989)) and match quantitatively in the dilute limit. Small sample simulations do not exhibit the stress anomaly at low solids packings, further confirming that large scale structure is the cause of the unusual stress curve behavior.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5185699
• Report Number(s): UCRL-JC-105346; CONF-901080--1; ON: DE92014774
• Country of Publication: United States
• Language: English

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