dc.description.abstract | Granular materials are very common in everyday life: salt, sugar, coffee, powder, sand and coal etc .
They are made of common substances but in some way their behavior is completely different from what we can see in homogeneous gases, liquids or solids.
In this thesis, we report on both experimental and theoretical investigation of flow of granular materials.
Recently, the phenomenon of particle segregation was found in both two dimensional rotating drum and three dimensional rotating cylinder.
In Chapter 2, "FRICTION-INDUCED SEGREGATION", we propose a model of two dimensional rotating drum which reproduces the phenomenon of radial segregation.
It is a simple algorithm for simulation of rotating drum. We considered a rectangular lattice forming bands moving around central point.
The main assumption is that the system takes place in the avalanches at the surface, whereas the motion of the grains in the bulk are equally adverted by the bulk flow.
In fact many practical industrial situations involve the vibration of powders and granulates as an important part of a fabrication process.
Recently, many attentions are focused on the study of granular materials lying on a vertically vibrating surface.
The heap formation is one of pattern formations in the vibrating system.
In Chapter 3, "HEAP FORMATION IN VERTICALLY VIBRATING GRAINS", we describe dynamic of heap formation and also construct a model to simulate heap formation using cellular automata.
In the landslide close to rivers, the collapses of nearby slopes are mainly due to the versions of the river bed.
Despite the practical importance of these avalanches, very little is known about the properties of these avalanches.
In Chapter 4, "AVALANCHES FROM A COLLAPSING GRANULAR PILE", we report of an experimental
investigation of the statistical properties of these type of avalanches.
It is found that two angles of repose are needed to describe the shape of a collapsing granular pile. | en_US |