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Caitano R, Garcimartín A, Zuriguel I. Anchoring Effect of an Obstacle in the Silo Unclogging Process. PHYSICAL REVIEW LETTERS 2023; 131:098201. [PMID: 37721817 DOI: 10.1103/physrevlett.131.098201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/20/2023] [Indexed: 09/20/2023]
Abstract
Contrary to the proven beneficial role that placing an obstacle above a silo exit has in clogging prevention, we demonstrate that, when the system is gently shaken, this passive element has a twofold effect in the clogging destruction process. On one side, the obstacle eases the destruction of weak arches, a phenomenon that can be explained by the pressure screening that it causes in the outlet proximities. But on the other side, we discover that the obstacle presence leads to the development of a few very strong arches. These arches, which dominate in the heavy tailed distributions of unclogging times, correlate with configurations where the number of particles contacting the obstacle from below are higher than the average; hence suggesting that the obstacle acts as an anchoring point for the granular packing. This finding may help one to understand the ambiguous effect of obstacles in the bottleneck flow of other systems, such as pedestrians evacuating a room or active matter in general.
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Affiliation(s)
- Rodrigo Caitano
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - Angel Garcimartín
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - Iker Zuriguel
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
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2
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Parisi DR, Wiebke LE, Mandl JN, Textor J. Flow rate resonance of actively deforming particles. Sci Rep 2023; 13:9455. [PMID: 37301896 DOI: 10.1038/s41598-023-36182-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Lymphoid organs are unusual multicellular tissues: they are densely packed, but the lymphocytes trafficking through them are actively moving. We hypothesize that the intriguing ability of lymphocytes to avoid jamming and clogging is in part attributable to the dynamic shape changes that cells undergo when they move. In this work, we test this hypothesis by investigating an idealized system, namely, the flow of self-propelled, oscillating particles passing through a narrow constriction in two dimensions (2D), using numerical simulations. We found that deformation allows particles with these properties to flow through a narrow constriction in conditions when non-deformable particles would not be able to do so. Such a flowing state requires the amplitude and frequency of oscillations to exceed threshold values. Moreover, a resonance leading to the maximum flow rate was found when the oscillation frequency matched the natural frequency of the particle related to its elastic stiffness. To our knowledge, this phenomenon has not been described previously. Our findings could have important implications for understanding and controlling flow in a variety of systems in addition to lymphoid organs, such as granular flows subjected to vibration.
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Affiliation(s)
- Daniel R Parisi
- Instituto Tecnológico de Buenos Aires (ITBA), CONICET, C.A. de Buenos Aires, Argentina.
| | - Lucas E Wiebke
- Instituto Tecnológico de Buenos Aires (ITBA), C.A. de Buenos Aires, Argentina
| | - Judith N Mandl
- Department of Physiology and McGill Research Centre on Complex Traits, McGill University, Montreal, Canada
| | - Johannes Textor
- Data Science group, Institute for Computing and Information Sciences, Radboud University, Nijmegen, The Netherlands
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3
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Araújo NAM, Janssen LMC, Barois T, Boffetta G, Cohen I, Corbetta A, Dauchot O, Dijkstra M, Durham WM, Dussutour A, Garnier S, Gelderblom H, Golestanian R, Isa L, Koenderink GH, Löwen H, Metzler R, Polin M, Royall CP, Šarić A, Sengupta A, Sykes C, Trianni V, Tuval I, Vogel N, Yeomans JM, Zuriguel I, Marin A, Volpe G. Steering self-organisation through confinement. SOFT MATTER 2023; 19:1695-1704. [PMID: 36779972 PMCID: PMC9977364 DOI: 10.1039/d2sm01562e] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
Self-organisation is the spontaneous emergence of spatio-temporal structures and patterns from the interaction of smaller individual units. Examples are found across many scales in very different systems and scientific disciplines, from physics, materials science and robotics to biology, geophysics and astronomy. Recent research has highlighted how self-organisation can be both mediated and controlled by confinement. Confinement is an action over a system that limits its units' translational and rotational degrees of freedom, thus also influencing the system's phase space probability density; it can function as either a catalyst or inhibitor of self-organisation. Confinement can then become a means to actively steer the emergence or suppression of collective phenomena in space and time. Here, to provide a common framework and perspective for future research, we examine the role of confinement in the self-organisation of soft-matter systems and identify overarching scientific challenges that need to be addressed to harness its full scientific and technological potential in soft matter and related fields. By drawing analogies with other disciplines, this framework will accelerate a common deeper understanding of self-organisation and trigger the development of innovative strategies to steer it using confinement, with impact on, e.g., the design of smarter materials, tissue engineering for biomedicine and in guiding active matter.
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Affiliation(s)
- Nuno A M Araújo
- Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal.
- Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Liesbeth M C Janssen
- Department of Applied Physics and Science Education, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
| | - Thomas Barois
- University of Bordeaux, CNRS, LOMA, UMR 5798, F-33400, Talence, France
| | - Guido Boffetta
- Department of Physics and INFN, University of Torino, via Pietro Giuria 1, 10125, Torino, Italy
| | - Itai Cohen
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York, USA
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York, USA
| | - Alessandro Corbetta
- Department of Applied Physics and Science Education, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
| | - Olivier Dauchot
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005, Paris, France
| | - Marjolein Dijkstra
- Soft condensed matter, Department of Physics, Debye institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC, Utrecht, The Netherlands
| | - William M Durham
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK
| | - Audrey Dussutour
- Research Centre on Animal Cognition (CRCA), Centre for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, 31062, AD, France
| | - Simon Garnier
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ, 07102, USA
| | - Hanneke Gelderblom
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
- Department of Applied Physics and J. M. Burgers Center for Fluid Dynamics, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
| | - Ramin Golestanian
- Max Planck Institute for Dynamics and Self-Organization (MPI-DS), 37077, Göttingen, Germany
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, 8093, Zürich, Switzerland
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ, Delft, The Netherlands
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Ralf Metzler
- Institute of Physics & Astronomy, University of Potsdam, Karl-Liebknecht-Str 24/25, D-14476, Potsdam-Golm, Germany
| | - Marco Polin
- Mediterranean Institute for Advanced Studies, IMEDEA UIB-CSIC, C/Miquel Marqués 21, 07190, Esporles, Spain
- Department of Physics, University of Warwick, Gibbet Hill road, CV4 7AL, Coventry, UK
| | - C Patrick Royall
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005, Paris, France
| | - Anđela Šarić
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - Anupam Sengupta
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, L-1511, Luxembourg
| | - Cécile Sykes
- Laboratoire de Physique de lÉcole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005, Paris, France
| | - Vito Trianni
- Institute of Cognitive Sciences and Technologies, CNR, Via San Martino della Battaglia 44, 00185, Rome, Italy
| | - Idan Tuval
- Mediterranean Institute for Advanced Studies, IMEDEA UIB-CSIC, C/Miquel Marqués 21, 07190, Esporles, Spain
| | - Nicolas Vogel
- Institute of Particle Technology, Friedrich-Alexander Universität Erlangen-Nürnberg, Cauerstrasse 4, 91058, Erlangen, Germany
| | - Julia M Yeomans
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Iker Zuriguel
- Departamento de Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, Pamplona, Spain
| | - Alvaro Marin
- Physics of Fluids Group, Mesa+ Institute, Max Planck Center for Complex Fluid Dynamics and J. M. Burgers Center for Fluid Dynamics, University of Twente, 7500AE, Enschede, The Netherlands.
| | - Giorgio Volpe
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
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4
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Echeverría-Huarte I, Shi Z, Garcimartín A, Zuriguel I. Pedestrian bottleneck flow when keeping a prescribed physical distance. Phys Rev E 2022; 106:044302. [PMID: 36397559 DOI: 10.1103/physreve.106.044302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
We present experimental results of pedestrian evacuations through a narrow door under a prescribed safety distancing of either 1.5 or 2 meters. In this situation, flow rate augments with pedestrian velocity due to a complete absence of flow interruptions or clogs. Accordingly, the evacuation improves when the prescribed physical distance is reduced, as this implies shortening the time lapses between the exit of consecutive pedestrians. In addition, the analysis of pedestrian trajectories reveals that the distance to the first neighbor in the evacuation process is rather similar to the one obtained when pedestrians were just roaming within the arena, hence suggesting that this magnitude depends more on the crowd state (desired speed, prescribed safety distance, etc.) than on the geometry where the pedestrian flow takes place. Also, an important difference in pedestrian behavior is observed when people are asked to walk at different speeds: whereas slow pedestrians evidence a clear preference for stop-and-go motion, fast walkers display detouring and stop-and-go behavior roughly in the same proportion.
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Affiliation(s)
- Iñaki Echeverría-Huarte
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - Zhigang Shi
- State Key Laboratory of Fire Science, University of science and technology of China, 230026, Hefei, China
| | - Angel Garcimartín
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - Iker Zuriguel
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
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5
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Alborzi S, Clark BG, Hashmi SM. Soft particles facilitate flow of rigid particles in a 2D hopper. SOFT MATTER 2022; 18:4127-4135. [PMID: 35582943 DOI: 10.1039/d2sm00318j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The flow of granular materials through narrow openings governs flow and process efficiency in a variety of industrial settings. As the use of soft particles and other soft micro-materials becomes more widespread in consumer products, we seek to understand characteristics of granular flows beyond powder flows. We study clogging through a 2D hopper in systems consisting of a combination of soft and rigid particles of different sizes and mixing fractions. Our experimental results show that soft particles play a lubricating role in the flow of rigid spheres due to their deformability and slick surface, but the size of rigid particles influences clogging more than the size of soft ones. We simulate our results using a modification of the Durian bubble model to accommodate mixtures of particles of different softness. Without any adjustable parameters, the simulation results capture the clogging probability of soft-rigid particle mixtures through a 2D hopper.
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Affiliation(s)
- Saeed Alborzi
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, USA
| | - Benjamin G Clark
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, USA
| | - Sara M Hashmi
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, USA
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
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6
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Rzezonka J, Chraibi M, Seyfried A, Hein B, Schadschneider A. An attempt to distinguish physical and socio-psychological influences on pedestrian bottleneck. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211822. [PMID: 35706660 PMCID: PMC9156912 DOI: 10.1098/rsos.211822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 05/04/2022] [Indexed: 05/03/2023]
Abstract
It has been realized that the distinction between social-psychological effects and physical effects in pedestrian crowds is complex, and so the relevance of social psychology for the properties of pedestrian streams is still discussed controversially. Although physics-based models appear to capture many properties rather accurately, it was argued that simple systems of self-driven particles could not explain certain emergent phenomena. In particular, results from a recent empirical study of pedestrian flow at bottlenecks have been interpreted as indicating the relevance of social psychology even in relatively simple scenarios of crowd dynamics. The study showed a surprising dependence of the density near the bottleneck on the width of the corridor leading to it. The density increased with increasing corridor width, although a wider corridor provides more space for pedestrians. It has been argued that this observation is a consequence of social norms, which trigger the effect by a preference for queuing in such situations. However, convincing evidence for this hypothesis is still missing. Here, we reconsider this scenario from a physics perspective using computer simulations of a simple microscopic velocity-based model.
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Affiliation(s)
- Jonas Rzezonka
- Institute for Advanced Simulation, Forschungszentrum Jülich GmbH, Julich, Germany
- School of Architecture and Civil Engineering, University of Wuppertal, Wuppertal, Germany
- Institute for Theoretical Physics, University of Cologne, Cologne, Germany
| | - Mohcine Chraibi
- Institute for Advanced Simulation, Forschungszentrum Jülich GmbH, Julich, Germany
| | - Armin Seyfried
- Institute for Advanced Simulation, Forschungszentrum Jülich GmbH, Julich, Germany
- School of Architecture and Civil Engineering, University of Wuppertal, Wuppertal, Germany
| | - Ben Hein
- School of Architecture and Civil Engineering, University of Wuppertal, Wuppertal, Germany
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7
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Pedestrian dynamics at the running of the bulls evidence an inaccessible region in the fundamental diagram. Proc Natl Acad Sci U S A 2021; 118:2107827118. [PMID: 34873035 DOI: 10.1073/pnas.2107827118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 11/18/2022] Open
Abstract
We characterize the dynamics of runners in the famous "Running of the Bulls" Festival by computing the individual and global velocities and densities, as well as the crowd pressure. In contrast with all previously studied pedestrian systems, we unveil a unique regime in which speed increases with density that can be understood in terms of a time-dependent desired velocity of the runners. Also, we discover the existence of an inaccessible region in the speed-density state diagram that is explained by falls of runners. With all these ingredients, we propose a generalization of the pedestrian fundamental diagram for a scenario in which people with different desired speeds coexist.
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8
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Chen ZH, Wu ZX, Guan JY. Twofold effect of self-interest in pedestrian room evacuation. Phys Rev E 2021; 103:062305. [PMID: 34271713 DOI: 10.1103/physreve.103.062305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 05/27/2021] [Indexed: 11/07/2022]
Abstract
Evacuation dynamics of pedestrians in a square room with one exit is studied. The movement of the pedestrians is guided by the static floor field model. Whenever multiple pedestrians are trying to move to the same target position, a game theoretical framework is introduced to address the conflict. Depending on the payoff matrix, the game that the pedestrians are involved in may be either hawk-dove or prisoner's dilemma, from which the reaped payoffs determine the capacities, or probabilities, of the pedestrians occupying the preferred vacant sites. The pedestrians are allowed to adjust their strategies when competing with others, and a parameter κ is utilized to characterize the extent of their self-interest. It is found that self-interest may induce either positive or negative impacts on the evacuation dynamics depending on whether it can facilitate the formation of collective cooperation in the population or not. Particularly, a resonance-like performance of evacuation is realized in the regime of prisoner's dilemma. The effects of placing an obstacle in front of the exit and the diversity of responses of the pedestrians to the space competition on the evacuation dynamics are also discussed.
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Affiliation(s)
- Ze-Hao Chen
- Institute of Computational Physics and Complex Systems, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Zhi-Xi Wu
- Institute of Computational Physics and Complex Systems, Lanzhou University, Lanzhou, Gansu 730000, China.,Lanzhou Center for Theoretical Physics and Key Laboratory of Theoretical Physics of Gansu Province, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Jian-Yue Guan
- Institute of Computational Physics and Complex Systems, Lanzhou University, Lanzhou, Gansu 730000, China.,Lanzhou Center for Theoretical Physics and Key Laboratory of Theoretical Physics of Gansu Province, Lanzhou University, Lanzhou, Gansu 730000, China
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9
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Systematic experimental investigation of the obstacle effect during non-competitive and extremely competitive evacuations. Sci Rep 2020; 10:15947. [PMID: 32994513 PMCID: PMC7525554 DOI: 10.1038/s41598-020-72733-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/04/2020] [Indexed: 11/08/2022] Open
Abstract
Although some experimental evidence showed that an obstacle placed in front of a door allows making people's evacuations faster, the efficacy of such a solution has been debated for over 15 years. Researchers are split between those who found the obstacle beneficial and those who could not find a significant difference without it. One of the reasons for the several conclusions lies in the variety of the experiments performed so far, both in terms of competitiveness among participants, geometrical configuration and number of participants. In this work, two unique datasets relative to evacuations with/without obstacle and comprising low and high competitiveness are analyzed using state-of-the-art definitions for crowd dynamics. In particular, the so-called congestion level is employed to measure the smoothness of collective motion. Results for extreme conditions show that, on the overall, the obstacle does not reduce density and congestion level and it could rather slightly increase it. From this perspective, the obstacle was found simply shifting the dangerous spots from the area in front of the exit to the regions between the obstacle and the wall. On the other side, it was however confirmed, that the obstacle can stabilize longitudinal crowd waves, thus reducing the risk of trampling, which could be as important (in terms of safety) as improving the evacuation time. However, under urgent, competitive, but non-extreme conditions, the obstacle generally had a positive effect, helping channeling the flow of pedestrians through the exit while facilitating their interactions.
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10
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Echeverría-Huarte I, Zuriguel I, Hidalgo RC. Pedestrian evacuation simulation in the presence of an obstacle using self-propelled spherocylinders. Phys Rev E 2020; 102:012907. [PMID: 32795081 DOI: 10.1103/physreve.102.012907] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/15/2020] [Indexed: 11/07/2022]
Abstract
We explore the role that the obstacle position plays in the evacuation time of agents when leaving a room. To this end, we simulate a system of nonsymmetric spherocylinders that have a prescribed desired velocity and angular orientation. In this way, we reproduce the nonmonotonous dependence of the pedestrian flow rate on the obstacle distance to the door. For short distances, the obstacle delays the evacuation because the exit size is effectively reduced; i.e., the distance between the obstacle and the wall is smaller than the door width. By increasing the obstacle distance to the door, clogging is reduced leading to an optimal obstacle position (maximum flow rate) in agreement with results reported in numerical simulations of pedestrian evacuations and granular flows. For further locations, however, a counterintuitive behavior occurs as the flow rate values fall again below the one corresponding to the case without obstacle. Analyzing the head-times distribution, we evidence that this new feature is not linked to the formation of clogs, but is caused by a reduction of the efficiency of the agent's instantaneous flow rate when the exit is not blocked.
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Affiliation(s)
- I Echeverría-Huarte
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - I Zuriguel
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - R C Hidalgo
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
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11
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Adrian J, Seyfried A, Sieben A. Crowds in front of bottlenecks at entrances from the perspective of physics and social psychology. J R Soc Interface 2020; 17:20190871. [PMID: 32343932 PMCID: PMC7211470 DOI: 10.1098/rsif.2019.0871] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This article presents an interdisciplinary study of physical and social psychological effects on crowd dynamics based on a series of bottleneck experiments. Bottlenecks are of particular interest for applications such as crowd management and design of emergency routes because they limit the performance of a facility. In addition to previous work on the dynamics within the bottleneck, this study focuses on the dynamics in front of the bottleneck, more specifically, at entrances. The experimental set-up simulates an entrance scenario to a concert consisting of an entrance gate (serving as bottleneck) and a corridor formed by barriers. The parameters examined are the corridor width, degree of motivation and priming of the social norm of queuing. The analysis is based on head trajectories and questionnaires. We show that the density of persons per square metre depends on motivation and also increases continuously with increasing corridor width, meaning that a density reduction can be achieved by a reduction of space. In comparison to other corridor widths observed, the narrowest corridor is rated as being fairer, more comfortable and as showing less unfair behaviour. Pushing behaviour is seen as ambivalent: it is rated as unfair and listed as a strategy for faster access.
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Affiliation(s)
- Juliane Adrian
- Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich, Germany
| | - Armin Seyfried
- Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich, Germany.,Faculty of Architecture and Civil Engineering, University of Wuppertal, Wuppertal, Germany
| | - Anna Sieben
- Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich, Germany.,Faculty of Social Sciences, Ruhr University Bochum, Bochum, Germany
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12
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Das R, Kumar M, Mishra S. Nonquenched rotators ease flocking and memorize it. Phys Rev E 2020; 101:012607. [PMID: 32069681 DOI: 10.1103/physreve.101.012607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Indexed: 02/03/2023]
Abstract
We introduce a minimal model for a two-dimensional polar flock with nonquenched rotators and show that the rotators make the usual macroscopic long-range order of the flock more robust than the clean system. The rotators memorize the flock-information which helps in establishing the robustness. Moreover, the memory of the rotators assists in probing the moving flock. We also formulate a hydrodynamic framework for the microscopic model that makes our study comprehensive. Using linearized hydrodynamics, it is shown that the presence of such nonquenched heterogeneities increases the sound speeds of the flock. The enhanced sound speeds lead to faster convection of information and consequently the robust ordering in the system. We argue that similar nonquenched heterogeneities may be useful in monitoring and controlling large crowds.
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Affiliation(s)
- Rakesh Das
- S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - Manoranjan Kumar
- S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - Shradha Mishra
- Department of Physics, Indian Institute of Technology (BHU), Varanasi 221005, India
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