Abstract:
This thesis explores the dynamical behavior of granular materials via experiments in a vertically
vibrated granular bed. Experiments are designed with the primary objective to understand
the pattern formation dynamics that manifests in a vertically-vibrated container filled with
mono-disperse spherical particles as well as binary mixtures of equal sized spherical particles of
different materials. While the aesthetically pleasing shapes and the novel phase-coexistence of
these patterns have generated curiosity, the question of underlying mechanism for their genesis,
in addition to their dynamics, must be addressed from a theoretical point of view in future.
In this thesis, we report, for the first time, (i) a variety of “phase-coexisting” patterns having
different spatial and temporal order, a novel “Ratcheting/Oscillatory” cluster, and the related
phase diagrams in vibrated binary mixtures, (ii) a novel unsteady dynamics of the so-called
“density-inverted” Leidenfrost state and (iii) the micro-structural signatures of the transition
from the “bouncing-bed” to the Leidenfrost state. All these new experimental results are awaiting
theoretical explanations.
