Now showing items 1-20 of 21

  • A differential equation for the flow rate during silo discharge Beyond the Beverloo rule 

    Madrid, Marcos; Darias, José; Pugnaloni, Luis (EPJ Web of Conferences, 2017)
    We present a differential equation for the flow rate of granular materials during the discharge of a silo. This is based in the energy balance of the variable mass system in contrast with the traditional derivations based ...
  • Apparent mass during silo discharge Nonlinear effects related to filling protocols 

    Peralta, Juan Pablo; Aguirre, María; Geminard, Jean Christophe; Pugnaloni, Luis (Elsevier, 2017)
    We study the evolution of the force exerted by a granular column on the bottom surface of a silo during its discharge. Previous to the discharge, we prepare the system using different filling procedures: distributed, i.e. ...
  • Arch based configurations in the volume ensemble of static granular systems 

    Slobinsky, D.; Pugnaloni, Luis (Journal of Statistical Mechanics: Theory and Experiment, 2015)
    We propose an alternative approach to count the microscopic static configurations of granular packs under gravity by considering arches. This strategy obviates the problem of filtering out configurations that are not ...
  • Arching during the segregation of two dimensional tapped granular systems Mixtures versus intruders 

    Uñac, Rodolfo; Benito, Jesica; Vidales, Ana María; Pugnaloni, Luis (Springer, 2014)
    We present numerical simulations of binary mixtures of granular disks subjected to tapping. We consider the size segregation process in terms of the arches formed by small and big particles. Although arching has been ...
  • Clogging transition of many particle systems flowing through bottlenecks 

    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 (Scientific Reports, 2014)
    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, ...
  • Clogging transition of vibration driven vehicles passing through constrictions 

    Patterson, G.; Fierens, P.; Sangiuliano Jimka, F.; König, P.; Garcimartín, A.; Zuriguel, Iker; Pugnaloni, Luis; Parisi, D. (American Physical Society, 2017)
    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 ...
  • Contact network topology in tapped granular media 

    Arévalo, Roberto; Pugnaloni, Luis; Zuriguel, Iker; Maza, Diego (American Physical Society, 2013)
    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 ...
  • Dynamic transition in conveyor belt driven granular flow 

    Cordero, Jose; Pugnaloni, Luis (Elsevier, 2015)
    We consider the flow of disks of diameter d driven by a conveyor belt of dynamic friction coefficient μ through an aperture on a flat barrier. The flow rate presents two distinct regimes. At low belt velocities v the flow ...
  • Effect of grain shape on the jamming of two dimensional silos 

    Goldberg, Ezequiel; Carlevaro, Manuel; Pugnaloni, Luis (EPJ Web of Conferences, 2017)
    We present discrete element method simulations of the discharge of silos in two dimensions. We study the effect of the grain shape on the clogging of small apertures, considering regular polygons and disks of equal mass. ...
  • Effect of particle shape and fragmentation on the response of particle dampers 

    Sánchez, Martín; Carlevaro, Manuel; Pugnaloni, Luis (SAGE Publications, 2014)
    A particle damper (PD) is a device that can attenuate mechanical vibrations thanks to the dissipative collisions between grains contained in a cavity attached to the vibrating structure. It has been recently suggested that, ...
  • Ergodic nonergodic transition in tapped granular systems; The role of persistent contacts 

    Gago, Paula; Maza, Diego; Pugnaloni, Luis (Papers in Physics, 2016)
    Static granular packs have been studied in the last three decades in the frame of a modi ed equilibrium statistical mechanics that assumes ergodicity as a basic postulate. The canonical example on which this framework is ...
  • Exact predictions from Edwards ensemble vs realistic simulations of tapped narrow two dimensional granular columns 

    Irastorza, Ramiro; Carlevaro, Manuel; Pugnaloni, Luis (Journal of Statistical Mechanics: Theory and Experiment, 2013)
    We simulate, via a discrete element method, the tapping of a narrow column of disks under gravity. For frictionless disks, this system has a simple analytical expression for the density of states in the Edwards volume ...
  • Experimental proof of faster is slower in systems of frictional particles flowing through constrictions 

    Pastor, Jose; Garcimartín, Angel; Gago, Paula; Peralta, Juan; Martín Gomez, Cesar; Ferrer, Luis; Maza, Diego; Parisi, Daniel; Pugnaloni, Luis; Zuriguel, Iker (American Physical Society, 2015)
    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 ...
  • First order phase transition during displacement of amphiphilic biomacromolecules from interfaces by surfactant molecules 

    Ettelaie, Rammile; Dickinson, Eric; Pugnaloni, Luis (Journal of Physics: Condensed Matter, 2014)
    The adsorption of surfactants onto a hydrophobic interface, already laden with a fixed number of polymers, is studied using the self consistent field (SCF) calculation method of Scheutjens and Fleer. For polymers having ...
  • Flow rate of polygonal grains through a bottleneck Interplay between shape and size 

    Goldberg, Ezequiel; Carlevaro, Manuel; Pugnaloni, Luis (Papers in Physics, 2015)
    We report two-dimensional simulations of circular and polygonal grains passing through an aperture at the bottom of a silo. The mass flow rate for regular polygons is lower than for disks\red{,} as observed by other authors. ...
  • On and off dynamics of a creeping frictional system 

    Blanc, Baptiste; Geminard, Jean Christophe; Pugnaloni, Luis (Springer, 2014)
    We report on the dynamics of a model frictional system submitted to minute external perturbations. The system consists of a chain of sliders connected through elastic springs that rest on an incline. By introducing cyclic ...
  • Relevance of system size to the steady state properties of tapped granular systems 

    Gago, Paula; Maza, Diego; Pugnaloni, Luis (American Physical Society, 2015)
    We investigate the steady-state packing fraction ϕ and force moment tensor Σ of quasi-two-dimensional granular columns subjected to tapping. Systems of different height h and width L are considered. We find that ϕ and Σ, ...
  • Structure of force networks in tapped particulate systems of disks and pentagons I Clusters and loops 

    Pugnaloni, Luis; Carlevaro, Manuel; Kramar, M; Mischaikow, K; Kondic, L (American Physical Society, 2016)
    The force network of a granular assembly, defined by the contact network and the corresponding contact forces, carries valuable information about the state of the packing. Simple analysis of these networks based on the ...
  • Structure of force networks in tapped particulate systems of disks and pentagons II Persistence analysis 

    Kondic, L.; Kramar, M.; Pugnaloni, Luis; Carlevaro, Manuel; Mischaikow, K. (American Physical Society, 2016)
    In the companion paper [Pugnaloni et al., Phys. Rev. E 93, 062902 (2016)], we use classical measures based on force probability density functions (PDFs), as well as Betti numbers (quantifying the number of components, ...
  • Tapped granular packings described as complex networks 

    Arévalo, Roberto; Pugnaloni, Luis; Maza, Diego; Zuriguel, Iker (Taylor and Francis, 2013)
    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 ...