Physics dissertation defense of Adones Dengal: Dynamics of a rotating sphere on free surface of vibrated granular materials

Date: 
Monday, November 12, 2018
To: 
Monday, November 12, 2018
Time: 
3:00 PM
To: 
5:00 PM
Venue: 
Faura Building, Room 106


The Department of Physics of the School of Science and Engineering of Ateneo de Manila University cordially invites you to a Physics Dissertation Defense by Adones B. Dengal this Monday, 12 November 2018, 3-5 PM, at Faura Building, Room 106. Mr. Dengal’s dissertation adviser is Dr. Joel T. Maquiling, while his panelists are Dr. Ramon M. Delos Santos, Dr. Raphael A. Guerrero, Dr. Gil Nonato Santos, and Dr. Quirino Sugon Jr.

Abstract

This study investigates the rotational dynamics of a low-density sphere on the free surface of vertically vibrated granular matter (VGM). The dynamical behavior of the sphere is influenced by the external energy input from an electromagnetic shaker which is proportional to ε, where ε is equal to the ratio between the square of the dimensionless acceleration Γ and the square of the vibration frequency f of the container. Empirical results reveal that as the VGM transits from local to global convection, an increase in ε generally corresponds to an increase in the magnitudes of the rotational ωRS and translational vCM velocities of the sphere, an increase in the observed tilting angle θbed of the VGM bed, and a decrease in the time twall it takes the sphere to roll down the tilted VGM bed and hit the container wall. During unstable convection, an increase in ε results in a sharp decrease in the sphere’s peak and mean ωRS and a slight increase in twall. For the range of ε values covered in this study, the sphere may execute persistent rotation, wobbling, or jamming depending on the vibration parameters and the resulting convective flow in the system.