Granular media : flow & agitations

Abstract

This thesis is about weakly driven granular flows and suspensions. Chapter 1 is an overview of the current knowledge of slow granular flows in so-called split-bottom geometries, which in essence consist of a disk rotating at the bottom of a container. In chapter 2 we study dry granular flows in this split-bottom geometry, both in the frictional, slow, rate-independent regime, and in the liquid-like, rate dependent regime which is reached for faster flows. Chapters 3-5 deal with the flow of suspensions in the same geometry. We improve the so-called index matched scanning technique, that allows 3D imaging of the suspensions. Also for the suspension we study both the slow, rate independent and the faster, rate dependent regime. In all cases we combine 2D and 3D imaging of the flow with rheological measurements. Chapter 6 is devoted to the rheology of dry, weakly vibrated granular media. In chapter 7 we revisit a classic experiment on the compaction of granular media.