FRLP - I+D+i - GRUTN - GMG

Permanent URI for this communityhttp://48.217.138.120/handle/20.500.12272/1760

Browse

Author: search.filters.author.Zuriguel, Iker

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Clogging transition of many particle systems flowing through bottlenecks
    (Scientific Reports, 2014) Zuriguel, Iker; Parisi, Daniel; Cruz Hidalgo, Raul; Lozano, Celia; Janda, Alvaro; Gago, Paula; Peralta, Juan; Ferrer, Luis; Pugnaloni, Luis; Clement, Eric; Maza, Diego; Pagonabarraga, Ignacio; Garcimartín, Angel
    When a large set of discrete bodies passes through a bottleneck, the flow may become intermittent due to the development of clogs that obstruct the constriction. Clogging is observed, for instance, in colloidal suspensions, granular materials and crowd swarming, where consequences may be dramatic. Despite its ubiquity, a general framework embracing research in such a wide variety of scenarios is still lacking. We show that in systems of very different nature and scale -including sheep herds, pedestrian crowds, assemblies of grains, and colloids- the probability distribution of time lapses between the passages of consecutive bodies exhibits a power-law tail with an exponent that depends on the system condition. Consequently, we identify the transition to clogging in terms of the divergence of the average time lapse. Such a unified description allows us to put forward a qualitative clogging state diagram whose most conspicuous feature is the presence of a length scale qualitatively related to the presence of a finite size orifice. This approach helps to understand paradoxical phenomena, such as the faster-is-slower effect predicted for pedestrians evacuating a room and might become a starting point for researchers working in a wide variety of situations where clogging represents a hindrance.
  • Thumbnail Image
    Item
    Experimental proof of faster is slower in systems of frictional particles flowing through constrictions
    (American Physical Society, 2015) Pastor, Jose; Garcimartín, Angel; Gago, Paula; Peralta, Juan; Martín Gomez, Cesar; Ferrer, Luis; Maza, Diego; Parisi, Daniel; Pugnaloni, Luis; Zuriguel, Iker
    The “faster-is-slower” (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [D. Helbing, I. J. Farkas, and T. Vicsek, Nature (London) 407, 487 (2000)]. FIS refers to the finding that, under certain conditions, an excess of the individuals' vigor in the attempt to exit causes a decrease in the flow rate. In general, this effect is identified by the appearance of a minimum when plotting the total evacuation time of a crowd as a function of the pedestrian desired velocity. Here, we experimentally show that the FIS effect indeed occurs in three different systems of discrete particles flowing through a constriction: (a) humans evacuating a room, (b) a herd of sheep entering a barn, and (c) grains flowing out a 2D hopper over a vibrated incline. This finding suggests that FIS is a universal phenomenon for active matter passing through a narrowing.
  • Thumbnail Image
    Item
    Clogging transition of vibration driven vehicles passing through constrictions
    (American Physical Society, 2017) Patterson, G.; Fierens, P.; Sangiuliano Jimka, F.; König, P.; Garcimartín, Angel; Zuriguel, Iker; Pugnaloni, Luis; Parisi, Daniel
    We report experimental results on the competitive passage of elongated self-propelled vehicles rushing through a constriction. For the chosen experimental conditions, we observe the emergence of intermittencies similar to those reported previously for active matter passing through narrow doors. Noteworthy, we find that, when the number of individuals crowding in front of the bottleneck increases, there is a transition from an unclogged to a clogged state characterized by a lack of convergence of the mean clog duration as the measuring time increases. It is demonstrated that this transition—which was reported previously only for externally vibrated systems such as colloids or granulars—appears also for self-propelled agents. This suggests that the transition should also occur for the flow through constrictions of living agents (e.g., humans and sheep), an issue that has been elusive so far in experiments due to safety risks.
  • Thumbnail Image
    Item
    Tapped granular packings described as complex networks
    (Taylor and Francis, 2013) Arévalo, Roberto; Pugnaloni, Luis; Maza, Diego; Zuriguel, Iker
    We characterize the structure of simulated two-dimensional granular packings using con- cepts from complex networks theory. The packings are generated by a simulated tapping protocol, which allows us to obtain states in mechanical equilibrium in a wide range of densi- ties. We show that our characterization method is able to discriminate non-equivalent states that have the same density. We do this by examining differences in the topological structure of the contact network of the packings. In particular, we find that the polygons of the network are specially sensitive probes for the contact structure. Additionally, we compare the network properties obtained in two different scenarios: the tapped and a compressed system.
  • Thumbnail Image
    Item
    Contact network topology in tapped granular media
    (American Physical Society, 2013) Arévalo, Roberto; Pugnaloni, Luis; Zuriguel, Iker; Maza, Diego
    We analyze the contact network of simulated two-dimensional granular packings in different states of mechanical equilibrium obtained by tapping. We show that topological descriptors of the contact network allow one to distinguish steady states of the same mean density obtained with different tap intensities. These equal-density states were recently proven to be distinguishable through the mean force moment tensor. In contrast, geometrical descriptors, such as radial distribution functions, bond order parameters, and Voronoi cell distributions, can hardly discriminate among these states. We find that small-order loops of contacts—the polygons of the network—are especially sensitive probes for the contact structure.