When a can containing one large ball and number of smaller ones is shaken, the rises to top, even when larger more dense than others. Similarly, mixture different sized particles will segregate by size shaken. An adaptation Monte Carlo method used study this segregation. The results show local, geometric mechanism which segregation produced. Segregation be distinguished from obvious sifting process occurs tiny grains filter down through interstices between particles.

In this paper we report measurements of collisional properties spheres using high-speed video analysis. These results agree with a simple collision operator. We study the size and velocity dependences coefficient restitution in normal direction. The experimental data are compared relevant models energy dissipation show existence two regimes. For large impact velocities plastic deformation model is good agreement our measurements, while for smaller viscoelastic gives qualitative agreement.

We report experiments on the rise time T of a single large sphere within sinusoidally vibrated bed (amplitude a) uniform particles (diameter d). At fixed acceleration, we identify three distinct behavioral regimes both from visual observations and typical increase with frequency f. observe two convective separated by critical and, for low high f, ``nonconvective'' regime. In latter, crystallizes size dependent is evidenced. show relevance nondimensional parameter $a/d$ deduce scaling law...

Three-dimensional granular dynamics simulations are carried out to investigate macroscopic behavior of materials subjected vibrations. Particles, idealized as smooth inelastic, uniform spheres, gravitationally loaded into a rectangular periodic cell having an open top and plane floor. Vibrations the bed subsequently imposed through sinusoidally oscillated Significant differences in character found, depending on strength applied floor accelerations Γ=aω2, even if boundary input energy is...

Three-dimensional discrete element simulations are carried out to investigate the behavior of a shallow bed inelastic, frictional spheres (of uniform diameter d), which energized by vertical sinusoidal oscillations plane floor at amplitude and frequency ω=2πf. We long-term instantaneous velocity fields as well evolution pressure tensor. Results show that onset convection reported in literature is not only determined acceleration, but also ratio a/d. In wide (L/d∼100) narrow persistent...

Using a combination of experimental techniques and discrete particle method simulations, we investigate the resonant behaviour dense, vibrated granular system. We demonstrate that bed particles driven by vibrating plate may exhibit marked differences in its internal energy dependent on specific frequency at which it is driven, even if corresponding to oscillations driving system held constant acceleration provided base remains consistently significantly higher than gravitational...

The density relaxation phenomenon is modeled using both Monte Carlo and discrete element simulations to investigate the effects of regular taps applied a vessel having planar floor filled with monodisperse spheres. Results suggest existence critical tap intensity which produces maximum bulk solids fraction. We find that mechanism responsible for an evolving ordered packing structure propagating upwards from plane floor.

Nuclear magnetic resonance is becoming an important experimental technique to study the behavior of moving granular materials because its unique ability measure concentration, velocity, and dissipation within bulk rather than only on surface. Of all common motions such assemblies particles, most difficult vibrating bed unsteady motion. This paper demonstrates a nuclear imaging method highly energetic beds by spatial scanning. In contrast Fourier imaging, scanning prevents scattering image...

In this paper, we compare the behaviours of two vibrofluidized granular systems, identical in terms their composition, geometry and driving parameters, differing only initial conditions. It is found that, by increasing strength with which a system initially excited, considerable differences composition dynamics persist even after returned to its typical value. The observed changes particle mobility packing density are shown result marked segregative behaviour for equivalent steady-state...

Using discrete particle simulations validated by experimental data acquired using the positron emission tracking technique, we study efficiency of energy transfer from a vibrating wall to system discrete, macroscopic particles. We demonstrate that even for fixed input wall, conveyed granular under excitation may vary significantly dependent on frequency and amplitude driving oscillations. investigate manner in which with is transferred depends variables determine key control parameters...

AbstractAbstractThe quality of a powder compact depends on the uniformity particle size distribution throughout its volume and retaining refined microstructure during final consolidation process. This paper deals with creation uniform green compacts from powders dynamic An overview basic issues problems concerning behaviour handling granular materials is presented, emphasising recent results segregation induced through vibrations occurring in flows. The implications production are introduced...

The change in bulk density or solids fraction that occurs when a vessel of granular materials is vibrated an important, industrially-relevant process. In this paper, we present findings from experiments and discrete element simulations on the relaxation behavior assemblies uniform spheres are vertically oscillated. Physical measurements fraction, qualitatively reproduced simulations, reveal noticeable trends data dependent vibration amplitude frequency. By carrying out extended 'phase' chart...

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Blackmore-Samulyak-Rosato (BSR) fields, originally developed as a means of obtaining reliable continuum approximations for granular flow dynamics in terms relatively simple integro-differential equations, can be used to model wide range physical phenomena.Owing results obtained one-dimensional configurations, it has been conjectured that BSR models fields with perfectly elastic interactions are completely integrable infinite-dimensional Hamiltonian systems.This conjecture is proved one space...