Measuring the steady state of pedestrian flow in bottleneck experiments

Liao, Wei-Tung; Tordeux, Antoine; Seyfried, Armin; Chraibi, Mohcine; Drzycimski, Kevin; Zheng, Xiaoping; Zhao, Ying

doi:10.1016/j.physa.2016.05.051

Cited by 58 publications

(35 citation statements)

References 24 publications

(64 reference statements)

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“…More importantly, it can also be seen that-in all the cases-the instantaneous flow is rather constant throughout the whole transit of the herd (no transient is manifested at the beginning or the end of the process). This is opposed to what was recently observed with pedestrians [32,33] where a clear transient, both at the beginning and at the end of the evacuation drill, was identified. Apart from looking at global magnitudes (such as flow rate or total transit time), we can gain further insight of the flow properties by looking at the passage time between consecutive individuals ( t).…”

Section: Resultscontrasting

confidence: 99%

“…To this end we have performed experiments with three different obstacle positions, evidencing that there is an optimum location: if the obstacle is too far, its effect is weak as the small pressure reduction is not able to cause a notable improvement; if the obstacle is too close, clogs start to appear between the doorjamb and the obstacle, as previously evidenced in granular silos [25] and in numerical simulations [24]. In addition, in this work we will take advantage of the large amount of data collected to unveil whether the flow of sheep through bottlenecks displays any transient behavior as already observed in humans [32,33].…”

Section: Introductionmentioning

confidence: 80%

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Effect of obstacle position in the flow of sheep through a narrow door

et al. 2016

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In a recent work [Phys. Rev. E 91, 022808 (2015)] it was reported that placing an obstacle in front of a gate has a beneficial effect in the flow of sheep through it. Here, we extend such results by implementing three different obstacle positions. We have observed that the flow is improved in two cases, while it worsens in the other one; the last instance happens when the obstacle is too close to the door. In this situation, the outcomes suggest that clogging develops between the doorjamb and the obstacle, contrary to the cases when the obstacle is farther, in which case clogging always occurs at the very door. The effectiveness of the obstacle (a strategy put forward to alleviate clogging in emergency exits) is therefore quite sensitive to its location. In addition, the study of the temporal evolution of the flow rate as the test develops makes evident a steady behavior during the entire duration of the entrance. This result is at odds with recent findings in human evacuation tests where the flow rate varies over time, therefore challenging the fairness of straightforward comparisons between pedestrian behavior and animal experimental observations.

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Section: Resultscontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 80%

Effect of obstacle position in the flow of sheep through a narrow door

et al. 2016

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“…It seems reasonable to think that the applied relevance of this finding is marginal, as most of real silos are wide enough to be in the asymptotic limit. Nevertheless, there are many other systems-such as particle rafts [35], pedestrian flows [36], and colloids [37]-where, commonly, the distance to the walls in the enclosure previous to the bottleneck is small and is therefore expected to affect clogging. Moreover, for the case of very narrow silos, this work raises new questions, such as if a small asymmetry of the outlet position is able to further prevent clogging or whether there is a smooth transition to a situation where the silo width equals the outlet size, i.e., the case of clogging in pipe flow [38,39].…”

Section: Discussionmentioning

confidence: 99%

Linking bottleneck clogging with flow kinematics in granular materials: The role of silo width

et al. 2017

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We demonstrate experimentally that clogging in a silo correlates with some features of the particle velocities in the outlet proximities. This finding, that links the formation of clogs with a kinematic property of the system, is obtained by looking at the effect that the position of the lateral walls of the silo has on the flow and clogging behavior. Surprisingly, the avalanche size depends nonmonotonically on the distance of the outlet from the lateral walls. Apart from evidencing the relevance of a parameter that has been traditionally overlooked in bottleneck flow, this nonmonotonicity supposes a benchmark with which to explore the correlation of clogging probability with different variables within the system. Among these, we find that the velocity of the particles above the outlet and their fluctuations seem to be behind the nonmonotonicity in the avalanche size versus wall distance curve.

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“…The density shows a relatively short plateau, which is due to the limited number of participants. Therefore, the steady state [29] at the measurement area is selected mainly according to the mean speed, which showcases a relatively more stable trend. The start and the end of the steady state are represented by the vertical dashed lines in Fig.8.…”

Section: Density and Speed Distributionmentioning

confidence: 99%

Experimental study on elderly pedestrians passing through bottlenecks

Ren¹,

Zhang²,

Cao³

et al. 2019

J. Stat. Mech.

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The aging of population is a social phenomenon in the world. In this study, series of controlled experiments were performed to investigate the movement characteristics of elderly pedestrians passing through bottlenecks. Similar self-organized phenomena to that of the young like 'zipper effect' and 'lane formation' are observed. The highest local density that appears in front of the exit in the experiment is beyond 4 m -2 . The time lapse between two consecutive pedestrians of the elderly is about 0.2 s longer than that of the young when the width is 0.5 m and 0.7 m. Besides, the difference decreases with the increasing exit width. A linear relation between flow and bottleneck width is obtained, while the flow of elders is lower than that of the young under the same width of exits. The waiting time of pedestrians can be divided into two stages when the bottleneck width is narrower than 0.8 m. The findings in this study will benefit the evacuation guidance as well as the facility design for elders.

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Measuring the steady state of pedestrian flow in bottleneck experiments

Abstract: Experiments with pedestrians could depend strongly on initial conditions. Comparisons

Cited by 58 publications

References 24 publications

Effect of obstacle position in the flow of sheep through a narrow door

Effect of obstacle position in the flow of sheep through a narrow door

Linking bottleneck clogging with flow kinematics in granular materials: The role of silo width

Experimental study on elderly pedestrians passing through bottlenecks

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