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Fluid Dynamics Colloquium

Monday, December 5, 2005, 4:00 pm
Cullimore Lecture Hall, Room 611
New Jersey Institute of Technology

Modeling Dense Granular Systems

Lou Kondic

Associate Professor

Department of Mathematical Sciences, NJIT

Abstract

Basic modeling approaches to granular/particulate systems are still unclear, in particular for dense (high volume fraction) ones. While kinetic theory has been successful in explaining some important features of low volume fraction systems, it is unclear that this powerful approach can be extended to dense ones. Alternatives include discrete element (molecular dynamics) and Monte-Carlo simulations, in addition to various models which are often derived using assumptions whose appropriateness is unclear. An example of a basic question which is just beginning to be answered is the basic type (elliptic/parabolic/hyperbolic) of continuous equations that could potentially describe granular systems.

After giving overview of the field, I will discuss few issues whose understanding may help to develop new models for granular systems. These will include some very basic ideas which we still do not understand well, such as the concept of granular temperature. Next I will concentrate on the particular question of signal propagation through sheared granular systems, and discuss connections to some systems that can be described using well known concepts of fluid dynamics and/or elasticity theory.