Statistical Properties of a Granular Gas Fluidized by Turbulent Air Wakes

López-Castaño, Miguel A.; González-Saavedra, Juan F.; Rodríguez‐Rivas, Álvaro; Reyes, Francisco Vega

doi:10.1007/978-3-030-55973-1_49

Cited by 4 publications

(5 citation statements)

References 15 publications

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“…For a vibrated monolayer of steel balls [24], a plateau appears in the MSD at φ ≈ 0.7. It is reported that the caging occurred at φ ≈ 0.7 for fluidized ping-pong balls (ρ = 0.08 g cm −3 ) [13], while for fluidized beads no caging was observed [6]. Fluidized bidispersed steel balls [5] exhibit strong caging at φ = 0.74 but do not show subdiffusion for φ < 0.64.…”

Section: Caging Effectmentioning

confidence: 98%

“…Actually many studies in recent years have found that various macroscopic, strongly dissipative (and thus out-of-equilibrium) systems such as particles agitated by turbulent airflow [3][4][5][6][7][8] or by mechanical vibration [9][10][11], can mimic Brownian behavior to an appreciable degree which has long been considered mainly in the context of energetically closed system. Thus far a variety of studies on macroscopic two-dimensional systems have been conducted [7,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Anomalous Diffusion in a Monolayer of Lightweight Spheres Fluidized in Airflow

Koyama,

Matsuno,

Noguchi

2021

Preprint

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This paper presents statistical analyses of random motions in a single layer of fluidized lightweight spherical particles. Foam polystyrene spheres were driven by an upward airflow through the sieve mesh, and their two-dimensional motion was acquired using image analysis. In the bulk region, the particle velocity distributions changed from Gaussian to heavy-tailed distribution as the bulk packing fraction φ b was increased. The mean square displacement of the particles exhibited transition to subdiffusion at much lower φ b than observed in previous studies using similar setup but with heavier particles. A slight superdiffusion and significant growth of the correlation length in the two-body velocity correlation was observed at further large φ b . The effect of the wall on the dynamics of the particles was also investigated and the anisotropy of the granular temperature was found to be a useful index to discriminate between the wall region and the bulk. The turbulence statistics in the wake of a particle indicated a strong wall-normal asymmetry of aerodynamic forcing as the "thermal" agitation in the wall region.

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Section: Caging Effectmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Anomalous Diffusion in a Monolayer of Lightweight Spheres Fluidized in Airflow

Koyama,

Matsuno,

Noguchi

2021

Preprint

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“…Furthermore, it has been reported recently that in a configuration of ping-pong balls rolling over a flat surface the KTHNY is, apparently, absent [26][27][28][29]; i.e., no hexatic phase could be detected. Instead, two consecutive phase transitions were detected, both with two coexisting phases.…”

Section: Introductionmentioning

confidence: 96%

Diffusion and Velocity Correlations of the Phase Transitions in a System of Macroscopic Rolling Spheres

Reyes¹,

Rodríguez‐Rivas²,

González-Saavedra³

et al. 2022

Preprint

Self Cite

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We study an air-fluidized granular monolayer, composed in this case of plastic spheres, which roll on a metallic grid. The air current is adjusted so that the spheres never loose contact with the grid, so that the dynamics may be regarded as pseudo two-dimensional (or two-dimensional, if the effects of sphere rolling are not taken into account). We find two surprising continuous transitions, both of them displaying two coexisting phases. Moreover, in all cases, we found the coexisting phases display strong energy non-equipartition. In the first transition, at weak fludization, a glassy phase coexists with a disordered fluid-like phase. In the second transition, a hexagonal crystal coexists with the fluid phase. We analyze, for these two-phase systems, the specific diffusive properties of each phase, as well as the velocity correlations. Surprisingly, we find a glass phase at very low packing fraction and for a wide range of granular temperatures. Both phases are characterized also by a strong anti-correlated velocities upon collision. Thus, the dynamics observed for this quasi two-dimensional system unveils phase transitions with peculiar properties, very different from the predicted behavior in well know theories for their equilibrium counterparts.

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“…An analysis is performed of the eventual departures from the KTHNY scenario when long-ranged hydrodynamic interactions would be relevant for a more complete understanding of the phase behavior in two-dimensional systems. Although this experimental configuration had been studied in a number of previous works [ 54 , 56 , 57 , 58 , 59 ], the focus was put on other phenomenology, and no detailed analyses were carried out on the phase behavior, except for more recent work where a generic description has been provided [ 56 , 59 ].…”

Section: Introductionmentioning

confidence: 99%

Diffusion and Velocity Correlations of the Phase Transitions in a System of Macroscopic Rolling Spheres

Reyes

Rodríguez‐Rivas

González-Saavedra

et al. 2022

Entropy

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We study an air-fluidized granular monolayer composed of plastic spheres which roll on a metallic grid. The air current is adjusted so that the spheres never lose contact with the grid and so that the dynamics may be regarded as pseudo two dimensional (or two dimensional, if the effects of the sphere rolling are not taken into account). We find two surprising continuous transitions, both of them displaying two coexisting phases. Moreover, in all the cases, we found the coexisting phases display a strong energy non-equipartition. In the first transition, at a weak fluidization, a glass phase coexists with a disordered fluid-like phase. In the second transition, a hexagonal crystal coexists with the fluid phase. We analyze, for these two-phase systems, the specific diffusive properties of each phase, as well as the velocity correlations. Surprisingly, we find a glass phase at a very low packing fraction and for a wide range of granular temperatures. Both phases are also characterized by strong anticorrelated velocities upon a collision. Thus, the dynamics observed for this quasi two-dimensional system unveil phase transitions with peculiar properties, very different from the predicted behavior in well-know theories for their equilibrium counterparts.

show abstract

Statistical Properties of a Granular Gas Fluidized by Turbulent Air Wakes

Cited by 4 publications

References 15 publications

Anomalous Diffusion in a Monolayer of Lightweight Spheres Fluidized in Airflow

Anomalous Diffusion in a Monolayer of Lightweight Spheres Fluidized in Airflow

Diffusion and Velocity Correlations of the Phase Transitions in a System of Macroscopic Rolling Spheres

Diffusion and Velocity Correlations of the Phase Transitions in a System of Macroscopic Rolling Spheres

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