The physics of granular systems

granular systems

Gutt, Gary Michael ; Haff, Peter K. (advisor)

University:California Institute of Technology

Department:Physics, Mathematics and Astronomy

关键词: granular systems;   

Others  :  https://thesis.library.caltech.edu/2307/1/Gutt_gm_1989.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

To gain an improved understanding of the physics of granular systems, investigations of two aspects of continuum theories of granular flows and a new paradigm for modelling granular systems are presented.The analogy between a flowing granular system and a molecular gas allows the adaptation of elements of the kinetic theory of gases to a continuum theory of granular flow. Two significant areas of difference between gases and granular materials are the additional degrees of freedom due to the spin and surface roughness of the grains and the boundary conditions between a granular flow and a bounding surface. Using techniques from the field of nonequilibrium thermodynamics, equations of motion and constitutive relations are obtained which include the effects of the spin and surface roughness of the grains. Also, boundary conditions on continuum theories for flows of smooth grains are presented, emphasizing the need to allow for several "slip" degrees of freedom.In order to obtain a more general description of large scale effects in granular systems involving both flowing and static assemblies of grains, a model is developed (the lattice grain dynamics paradigm) for simulating systems containing large numbers of grains. This model is based on concepts from the fields of cellular automata, lattice gases, and particle dynamics simulations.