Interactions in Granular Media

Abstract

The physics of granular materials concerns itself with real-life situations in which solid particles typically find themselves in a gas environment (usually air) or in a liquid. The properties of granulars depend primarily on the nature of the interactions between the particles themselves, but also between the particles and their environment. When the influence of the environment can be neglected, we deal with what is called dry granular materials. Otherwise, the resulting systems can be quite complex and exhibit a variety of behaviors depending on the media involved. This field of study, which has considerable industrial applications, encompasses a broad range of media, from pastes to liquid muds to porous materials. It has been the object of a large number of studies. While this topic is in the midst of rapid development, it remains largely outside the scope of this book, which focuses deliberately on a highly simplified approach in which interactions are reduced to a minimum, as opposed to the much more complicated interactions characteristic of “moist” granular materials. In what follows, we shall concern ourselves almost exclusively with dry granulars. These have not always commanded much in the way of sustained interest on the part of the physics research community, in spite of the many different possible behaviors and fundamental nature of the problems involved, which would normally be expected to pique the curiosity of physicists and industrial engineers.