Phase-coexisting patterns, horizontal segregation, and controlled convection in vertically vibrated binary granular mixtures

Ansari, Istafaul H.; Rivas, Nicolas; Alam, Meheboob

doi:10.1103/physreve.97.012911

Cited by 7 publications

(7 citation statements)

References 40 publications

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“…The primary motivation of using a larger-box is to ascertain whether the "monolayer" vibrofluidized bed admits convective motion whose origin may then be tied to the instability of the Leidenfrost state. Similar transition has been reported previously [36,38,39], however, in a "quasi-2D" box (with a depth of few particle diameters, W/d ≈ 5) as well as in a 3D-box. It was speculated in Ref.…”

Section: B Genesis Of Convection From Leidenfrost State: Multi-roll T...supporting

confidence: 88%

“…1b). This particle-filled container is mounted on an electromagnetic shaker (of Ling Dynamics System) via a circular head expander [38,39], and is vibrated vertically using a sine-wave of the form:…”

Section: A Experimental Protocol and Control Parametersmentioning

confidence: 99%

“…The granular particles held in the vibrating container are illuminated with two white LED light sources of power 25W , positioned at an oblique angle facing towards the container from both sides. Such type of lighting arrangement provided uniform lighting over the region of interest [38,39]. We employed a high-speed camera (IDT MotionPro Y4S3), mostly at a frame rate of 1000 frames per second, to capture the temporal evolution of the collective motion of particles.…”

Section: A Experimental Protocol and Control Parametersmentioning

confidence: 99%

“…The latter finding implies that two successive bifurcations from a "sub-harmonic" wavy-state to the Leidenfrost state resulted to the onset of convection at large particle loadings. It must be noted that the temporal-order of the Leidenfrost state was never quantified [31,36,38,39] via experiments, but it appears to be a quasi-steady or steady state from the related theoretical analyses [35,40,41]. In any case, the convection-rolls found at strong shaking (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed

Ansari

Alam

2016

Phys. Rev. E

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Experiments are conducted in a two-dimensional monolayer vibrofluidized bed of glass beads, with a goal to understand the transition scenario and the underlying microstructure and dynamics in different patterned states. At small shaking accelerations (Γ=Aω^{2}/g<1, where A and ω=2πf are the amplitude and angular frequency of shaking and g is the gravitational acceleration), the particles remain attached to the base of the vibrating container; this is known as the solid bed (SB). With increasing Γ (at large enough shaking amplitude A/d) and/or with increasing A/d (at large enough Γ), the sequence of transitions/bifurcations unfolds as follows: SB ("solid bed") to BB ("bouncing bed") to LS ("Leidenfrost state") to "2-roll convection" to "1-roll convection" and finally to a gas-like state. For a given length of the container, the coarsening of multiple convection rolls leading to the genesis of a "single-roll" structure (dubbed the multiroll transition) and its subsequent transition to a granular gas are two findings of this work. We show that the critical shaking intensity (Γ_{BB}^{LS}) for the BB→LS transition has a power-law dependence on the particle loading (F=h_{0}/d, where h_{0} is the number of particle layers at rest and d is the particle diameter) and the shaking amplitude (A/d). The characteristics of BB and LS states are studied by calculating (i) the coarse-grained density and temperature profiles and (ii) the pair correlation function. It is shown that while the contact network of particles in the BB state represents a hexagonal-packed structure, the contact network within the "floating cluster" of the LS resembles a liquid-like state. An unsteadiness of the Leidenfrost state has been uncovered wherein the interface (between the floating cluster and the dilute collisional layer underneath) and the top of the bed are found to oscillate sinusoidally, with the oscillation frequency closely matching the frequency of external shaking. Therefore, the granular Leidenfrost state is a period-1 wave as is the case for the BB state.

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Section: B Genesis Of Convection From Leidenfrost State: Multi-roll T...supporting

confidence: 88%

Section: A Experimental Protocol and Control Parametersmentioning

confidence: 99%

Section: A Experimental Protocol and Control Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed

Ansari

Alam

2016

Phys. Rev. E

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“…Heavier particles will tend to settle at the bottom of the bed, while lighter particles will rise to the top due to the upward force of buoyancy. This mechanism is driven by the density differences between particles, which causes them to sort themselves out according to their weight 27,39 . In the study by Yogi et al 35 , the authors examined the mixing behavior of multi-component mixtures in a vibrated packed bed.…”

Section: Introductionmentioning

confidence: 99%

Influence of aspect ratio of ellipsoidal particles on mixing in vibrated packed bed using DEM

Khatoon

Kumar

Yogi

et al. 2023

Preprint

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The uniform mixing of particles is crucial in many industrial applications. In industries, most granular materials are nonspherical, with ellipsoids being a common deviation from the sphere. The study employs the DEM model to investigate the mixing of a binary mixture in a vibrated packed bed with fixed amplitude and frequency. The study explores the behavior of the binary mixture of coarse and fine particles, with one particle being ellipsoid of aspect ratios (0.25-3.0) and the other being a sphere. The subdomain mixing index quantifies the mixing. The mixing of binary mixtures is determined by the aspect ratio of coarse and fine particles. The mixing efficiency is indicated by the average velocity of reference spherical particles, reflecting the convection strength within the bed. The results show higher average velocity in an ellipsoidal-sphere mixture than in a sphere-sphere mixture. The DEM results are validated with an identical experimental system.

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Influence of aspect ratio of ellipsoidal particles on mixing in vibrated packed bed using discrete element method

Khatoon,

Kumar,

Yogi

et al. 2024

AIChE Journal

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The uniform mixing of particles is crucial in many industrial applications. In industries, most granular materials are nonspherical, with ellipsoids being a common deviation from the sphere. The study employs the DEM model to investigate the mixing of a binary mixture in a vibrated packed bed with fixed amplitude and frequency. The study explores the behavior of the binary mixture of coarse and fine particles, with one particle being ellipsoid of aspect ratios (0.25–3.0) and the other being a sphere. The subdomain mixing index quantifies the mixing. The mixing of binary mixtures is determined by the aspect ratio of coarse and fine particles. The mixing efficiency is indicated by the average velocity of reference spherical particles, reflecting the convection strength within the bed. The results show higher average velocity in an ellipsoidal‐sphere mixture than in a sphere‐sphere mixture. The DEM results are validated with an identical experimental system.

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Phase-coexisting patterns, horizontal segregation, and controlled convection in vertically vibrated binary granular mixtures

Cited by 7 publications

References 40 publications

Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed

Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed

Influence of aspect ratio of ellipsoidal particles on mixing in vibrated packed bed using DEM

Influence of aspect ratio of ellipsoidal particles on mixing in vibrated packed bed using discrete element method

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