LLNL (Lawrence Livermore National Library) Granular Solids Flow Project: Quarterly Report, October-December 1987

摘要

This project is directed toward obtaining a fundamental understanding of the flow behavior of granular solids and multi-phase solids-containing systems. Here we report progress in two new areas of study, quasi-static deformations and suspension rheology. Discrete particle computer models have the potential for becoming very useful tools for understanding such problems. We have begun a reexamination of our computer models to see how they can most effectively be applied to the many granular solids flow problems that involve quasi-static deformations. We have carefully reviewed our models of tagential friction between elastic spheres in contact, and have developed improved algorithms. We have also initiated development of more complex models that include adhesive surface forces and non-constant coefficients of friction. These new algorithms will be added to the 3DSHEAR model in the near future. We are examining various approaches to determine the rheologic properties of suspensions. As part of this effort we are developing a general numerical method to calculate the hydrodynamic interactions for arbitrary assemblies of spheres in suspension. The first results with this method involve assemblies of a small number of equal size spheres with periodic boundaries. The method utilizes effective induced forces on the sphere surfaces and approximately accounts for the effects of all spheres in the system (including their periodic images). The numerical results agree with analytic expansions valid when the solid particles are far apart, and with known results for periodic arrays containing one or two particles per unit cell. Further extensions of this work are planned. (ERA citation 13:031489)