Experimental study of a granular flow in a vertical pipe: A spatiotemporal analysis

Aider, Jean-Luc; Sommier, Nathalie; Raafat, Tareck; Hulin, Jean-Pierre

doi:10.1103/physreve.59.778

Cited by 42 publications

(55 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3,4 These waves induce potentially destructive pressure transients on the inner-wall of the pipe and provide the mechanism responsible for the intermittent behavior of the flow. Although the dynamics of density waves in granular pipe flows have been studied extensively in the past both experimentally [5][6][7][8][9][10] and through different types of models, 3,4,[11][12][13][14][15][16][17][18][19] it is still a challenging problem to control the mass flux of the granular material flowing through a pipe. For example, Zuriguel et al 20 showed how insertion of an obstacle just above the outlet of a silo can significantly reduce the probability that the granular flow is arrested due to the formation of an arch blocking the silo's outlet.…”

Section: Introductionmentioning

confidence: 99%

Helical inner-wall texture prevents jamming in granular pipe flows

2015

View full text Add to dashboard Cite

Granular pipe flows are characterized by intermittent behavior and large, potentially destructive solid fraction variations in the transport direction. By means of particle-based numerical simulations of gravity-driven flows in vertical pipes, we show that it is possible to obtain steady material transport by adding a helical texture to the inner-wall of the pipe. The helical texture leads to a more homogeneous mass flux along the pipe, prevents the emergence of large density waves and substantially reduces the probability of plug formation thus avoiding jamming of the particulate flow. We show that the granular mass flux Q through a pipe of diameter D with a helical texture of wavelength l follows the equation

show abstract

Section: Introductionmentioning

confidence: 99%

Helical inner-wall texture prevents jamming in granular pipe flows

2015

View full text Add to dashboard Cite

show abstract

“…Bertho et al [8] presented experiments on density waves performed using an experimental setup similar to that of Raafat et al [9] and Aider et al [7]. The vertical tube (D = 3 mm, 1.25 m long) and the glass beads (d = 0.125 mm glass beads) were roughly the same as that of Aider et al [7], and a linear CCD camera was used.…”

mentioning

confidence: 98%

“…The vertical tube (D = 3 mm, 1.25 m long) and the glass beads (d = 0.125 mm glass beads) were roughly the same as that of Aider et al [7], and a linear CCD camera was used. In addition, capacitance sensors were used to measure the compactness of grains at two different locations, and the pressure distribution was also measured.…”

mentioning

confidence: 99%

Length scale of density waves in the gravitational flow of fine grains in pipes

Franklin

Alvarez

2014

J Braz. Soc. Mech. Sci. Eng.

View full text Add to dashboard Cite

Gravitational flow of grains in pipes is frequently encountered in industry. When the grains and pipes are size-constrained, granular flow may result in density waves consisting of alternate high-and low-compactness regions. This paper discusses the length scale of density waves that appear when fine grains fall vertically in pipes. A one-dimensional model and a linear stability analysis of the model are presented. The analysis suggests the presence of long-wavelength instability for the most unstable mode, moreover, a cut-off wavenumber from which the length scale is estimated. Finally, the model results are compared to experimental data.

show abstract

“…We also found an oscillatory solution in the linearly unstable region and its period is not commensurate with the periodicity of the car index space. The oscillatory solution has some features in common with the synchronized flow observed in real traffic.KEYWORDS: optimal velocity model, traffic flow, granular pipe flow, open boundary condition, stability of uniform solutionThe traffic flow on a highway 1, 3, 2, 4, 5) and the granular pipe flow 6,7,8,9,10) are similar in a number of characteristics. Both consist of discrete elements following dissipative dynamics, both are quasi one-dimensional systems, and spontaneous density waves with the power law occur in both systems.…”

mentioning

confidence: 99%

Stability Analysis of Optimal Velocity Model for Traffic and Granular Flow under Open Boundary Condition

Mitarai

Nakanishi

1999

J. Phys. Soc. Jpn.

View full text Add to dashboard Cite

We analyzed the stability of the uniform flow solution in the optimal velocity model for traffic and granular flow under the open boundary condition. It was demonstrated that, even within the linearly unstable region, there is a parameter region where the uniform solution is stable against a localized perturbation. We also found an oscillatory solution in the linearly unstable region and its period is not commensurate with the periodicity of the car index space. The oscillatory solution has some features in common with the synchronized flow observed in real traffic.KEYWORDS: optimal velocity model, traffic flow, granular pipe flow, open boundary condition, stability of uniform solutionThe traffic flow on a highway 1, 3, 2, 4, 5) and the granular pipe flow 6,7,8,9,10) are similar in a number of characteristics. Both consist of discrete elements following dissipative dynamics, both are quasi one-dimensional systems, and spontaneous density waves with the power law occur in both systems. To understand the common structure of such phenomena, both discrete and continuous models have been suggested and have succeeded in reproducing some aspects of the spatiotemporal patterns. 8,11,12,13,14,15,16,17) In recent years, a car-following model, termed the "optimal velocity model" (OV model), was proposed. 11, 12)The model is realistic enough to be able to reproduce a spontaneous traffic jam as in real traffic, but simple enough to be regarded as a model of granular pipe flow without much modification. In fact, a model similar to the OV model has been proposed as a granular flow model and it has been demonstrated to exhibit power law behavior in the power spectra of the density wave in certain situations. 8)Even though a number of analyses of the OV model have been performed, most of them were conducted under the periodic boundary condition (PBC).11, 12, 13) The PBC corresponds to the situation that cars run in a circuit, but it is not suitable for most situations in real traffic observations. When we consider the situation of granular pipe flow, the PBC is quite unrealistic. Furthermore, from the experimental results of the granular pipe flow, it has been suggested that the condition of the downstream boundary is important. 9)In the present work, we investigate the OV model under the open boundary condition (OBC), and examine the effects of the boundary condition on the stability of the system.The OV model is a dynamical model for a onedimensional system which consists of discrete elements; the elements can be cars or grain particles, but they tend * E-mail: namiko@stat.phys.kyushu-u.ac.jp * * E-mail: naka4scp@mbox.nc.kyushu-u.ac.jp to run at the speed determined by a local configuration. When the (n + 1)th car precedes the nth car (Fig. 1) and the position of the nth car at the time t is denoted by x n (t), then the dynamics is governed by the equation of motionẍwhere b n (t) represents the headway of the nth car defined byand the dot denotes the time derivative. Here, a is a sensitivity constant and U (b) is the optimal v...

show abstract

Experimental study of a granular flow in a vertical pipe: A spatiotemporal analysis

Cited by 42 publications

References 19 publications

Helical inner-wall texture prevents jamming in granular pipe flows

Helical inner-wall texture prevents jamming in granular pipe flows

Length scale of density waves in the gravitational flow of fine grains in pipes

Stability Analysis of Optimal Velocity Model for Traffic and Granular Flow under Open Boundary Condition

Contact Info

Product

Resources

About