| dc.description.abstract | This thesis investigates the phenomenon of brazil nut effect in a quasi-two-dimensional
vertical vibrating bed by changing the aspect ratio of the intruder with the same mass, volume
and density. In order to capture real-time photos of particles and analyze them, a high-speed
camera was set up and use PTV (Particle Tracking Velocimetry) for subsequent analysis, and
the transport properties of particles such as rise time and velocity, granular temperature, and
diffusion coefficient were discussed. After a series of experiments and analysis, changing the
size of intruder will indeed affect the separation behavior. Intruder with longer horizontal
lengths are more difficult to ascend during the process of ascending, so the ascending time is
longer than those with shorter lengths. This value is also reflected in the rising speed. The longer
the intruder are, the slower the rising speed is. Because the bottom space generated by each
oscillation of the longer large particles is larger, and the background particles need to be filled
down to increase the number. Long intruder not only affect the number of particles at the bottom,
but also hinder the exchange movement of particles up and down to a certain extent. It is
because of these two reasons why the particles with the same bulk density have different
ascending behaviors.At the same time, we also measured the particle temperature to determine
whether the placement of different intruder would affect the overall kinetic energy of the system.
It was found that the overall system energy did not change whether long or short intruder were
placed. Finally, in order better understand the changes caused by different intruder, the selfdiffusion
coefficient at the bottom of the intruder was measured. It can be found that although
the energy received inside the system is the same, due to the influence of the size of the intruder,
the Intruder have different degrees of fluidization at the bottom, which in turn cause differences
in rise time between them. | en_US |