Effect of local perturbation on axially segregated binary granular mixture rotated on a horizontal cylinder

Date

4-2014

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Junius Andre F. Balista

Abstract

We investigated the effect of local perturbation on the evolution of axial band patterns of binary mixture of granular materials inside a rotating horizontal cylinder. We deliberately generated axial segregation by choosing the appropriate rotation rate and grain combination. The mixture consisted of large rough grains of sand (diameter range: 0.098 to 0.150 cm) and small fine grains of sand (diameter range: 0.046 to 0.086 cm.) We successfully produced axial bands in a horizontal cylinder rotating at 60 rpm to 80 rpm at increments of 5 rpm. Then, we perturbed the axially segregated granular material column by expanding and compressing one end of the column using a rubber baloon and observing the effect on the behavior of the bands. We analyzed the temporal and spatial characteristics of the axial bands by determining the range, speed of propagation and dissipation of the deformation. We observed that the effect of local perturbation is local and persists for a long time by order of magnitude of 10^2 to 10^6 with an average decay time constant ranging from 17 to 90 seconds. Also, there were time delays in the propagation along the granular media. These results suggest that a binary mixture of granular materials inside an axially rotated cylinder still behaved differently from solid, liquid or gas. These results could provide insights and impetus for deeper understanding of granular materials.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2014 P51 /A85

Document Type

Thesis

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