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Clogging in bottlenecks: from inert particles to active matter

Clogging in bottlenecks: from inert particles to active matter. http://www.unav.es/centro/gralunarlab. People involved: Luis Miguel Ferrer (Veterinary Faculty, Zaragoza) Alvaro Janda (Engineering School, Edinburgh) Geoffroy Lumay (GRASP, Liège) Celia Lozano (University of Navarra)

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Clogging in bottlenecks: from inert particles to active matter

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  1. Clogging in bottlenecks: from inert particles to active matter http://www.unav.es/centro/gralunarlab People involved: • Luis Miguel Ferrer (Veterinary Faculty, Zaragoza) • Alvaro Janda (Engineering School, Edinburgh) • Geoffroy Lumay (GRASP, Liège) • Celia Lozano (University of Navarra) • Diego Maza (University of Navarra) • Angel Garcimartín (University of Navarra) Iker Zuriguel iker@unav.es Dpto. Física y Mat. Aplicada Universidad de Navarra 31080 Pamplona, Spain. iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  2. Clogging in bottlenecks Traffic Grains (Picture from K. To, PRL 2001) Traffic Panic flow Embolization with microparticles iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  3. Clogging in silos R Avalanche size s: number of fallen grains Particle passing probability: p Avalanche size: n(s) = ps · (1-p) Exponential distributions: characteristic size and time, well defined averages. p Mean avalanche: <s> = (1-p) iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  4. Clogging in silos Mean avalanche size Flow rate Divergence or not? Critical R? Modified Beverloo expression A. Janda et al. EPL 2008 A. Janda et al. PRL 2012 iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  5. Clogging in silos in the presence of an obstacle iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  6. Clogging in silos in the presence of an obstacle I. Zuriguel et al. PRL 2011 <s> may increase more than 100 times. iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  7. Clogging in silos in the presence of an obstacle I. Zuriguel et al. PRL 2011 <s> may increase more than 100 times. The flow rate is not affected. Flow rate Mean avalanche size iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  8. Clogging in crowd dynamics… Helbing et al. Nature, 2000. Transportation Science, 2005. Clogs do not arrest the flow completely. The burst sizes can be measured (in number of people) Obstacle effect An obstacle properly placed in front of the exit leads to an improvement of the evacuation. Clogs and the evacuation time are reduced. 6 tests without obstacle. 4 tests with obstacle. iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  9. Clogging with sheep: Cubel (Zaragoza) Video-surveillance system iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  10. Experimental procedure Daily, sheep are taken out of the yard. The yard is cleaned and food is placed inside it. When the yard is opened again, all the sheep crowd together in front of the door. Door width = 77 cm Sheep width ~ 35 cm (Soft) Around 100 sheep The experiment consists on: 20 tests without obstacle 20 tests with an obstacle of 117 cm diameter placed 80 cm behind the door (with the same sheep). iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  11. Experiment without obstacle iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  12. Clogging times, burst size… time iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  13. Clogging times, burst size… time Clog “Burst” (burst size s = 17) tCi tCi+1 iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  14. Clogging and unclogging of sheep Clogging time: power-law tail withoutobstacle with obstacle A. Clauset, C. R. Shalizi and M. E. J. Newman, “Power-Law Distributions in Empirical Data” SIAM Review 51, 661-703 (2009) iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  15. Clogging and unclogging of sheep Clogging time: power-law tail Histogram of burst sizes s/<s>: an exponential withoutobstacle with obstacle with obstacle without obstacle A. Clauset, C. R. Shalizi and M. E. J. Newman, “Power-Law Distributions in Empirical Data” SIAM Review 51, 661-703 (2009) iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  16. But the dynamics in silos are completely different… …once the system is clogged, the flow is not resumed by itself. Vibrated silo. iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  17. Vibrated silo • Let the grains flow until an arch forms and stops the outpouring. • Apply a vibration (constant amplitude G, constant frequency). • Detect the arch breaking and measure the time it has taken. • Empty the silo and repeat the experience. vibrating plate iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  18. Vibrated silo: avalanche size Exponential distributions A. Janda, D. Maza, A. Garcimartín, E. Kolb, J. Lanuza and E. Clément. EPL 87 (2009), 24002. C. Mankoc, A. Garcimartín, I. Zuriguel, D. Maza and L. A. Pugnaloni. PRE 80 (2009), 011309. The time that it takes the system to clog is well defined iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  19. Vibrated silo: clogging time G= 0.10 • 0.15 • 0.20 • 0.26 a= 1.6 1.9 2.0 2.2 iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  20. Vibrated silo: clogging time G= 0.10 • 0.15 • 0.20 • 0.26 a ≥ 2 The mean of the distribution converges. a< 2 The mean of the distribution does not converge. a= 1.6 1.9 2.0 2.2 iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  21. Vibrated silo: clogging time G= 0.10 • 0.15 • 0.20 • 0.26 a ≥ 2 The mean of the distribution converges. a< 2 The mean of the distribution does not converge. a= 1.6 1.9 2.0 2.2 • R = 4.00 • 4.50 • 4.65 • 4.76 • 4.84 a= 1.7 1.9 2.0 2.2 2.3 iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  22. Vibrated silo: clogging time G= 0.10 • 0.15 • 0.20 • 0.26 a ≥ 2 The mean of the distribution converges. a< 2 The mean of the distribution does not converge. a= 1.6 1.9 2.0 2.2 • R = 4.00 • 4.50 • 4.65 • 4.76 • 4.84 a=1.9 High layer of grains a= 1.7 1.9 2.0 2.2 2.3 P a=4.7 Low layer of grains iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

  23. Summary. • Avalanche and burst size distributions  exponential decay. • Clogging time distributions  power-law decays with exponent (a). • a< 2  mean clogging time diverges, average flow rate cannot be defined. • Going from a≥ 2 to a< 2 can be viewed as a clogging transition. • In a vibrated silo, the system can be unclogged increasing G or R. • Placing the obstacle in the sheep case has a similar effect (decreasing a) than reducing the layer of grains in a vibrated silo (pressure?). Department of Physics and Applied Mathematics Nonlinear transport, dynamics and fluctuations in condensed matter physics.

  24. Summary. • Avalanche and burst size distributions  exponential decay. • Clogging time distributions  power-law decays with exponent (a). • a< 2  mean clogging time diverges, average flow rate cannot be defined. • Going from a≥ 2 to a< 2 can be viewed as a clogging transition. • In a vibrated silo, the system can be unclogged increasing G or R. • Placing the obstacle in the sheep case has a similar effect (decreasing a) than reducing the layer of grains in a vibrated silo (pressure?). Work in progress. • Do people behave like sheep? (D. Parisi, UBA) • Can this be generalized to colloids? (R. Cruz-Hidalgo & I. Pagonabarraga) Department of Physics and Applied Mathematics Nonlinear transport, dynamics and fluctuations in condensed matter physics.

  25. Clogging in bottlenecks: from inert particles to active matter Thank you! http://www.unav.es/centro/gralunarlab People involved: • Luis Miguel Ferrer (Veterinary Faculty, Zaragoza) • Alvaro Janda (Engineering School, Edinburgh) • Geoffroy Lumay (GRASP, Liège) • Celia Lozano (University of Navarra) • Angel Garcimartín (University of Navarra) • Diego Maza (University of Navarra) Iker Zuriguel iker@unav.es Dpto. Física y Mat. Aplicada Universidad de Navarra 31080 Pamplona, Spain. iker@unav.es http://www.unav.es/centro/gralunarlab 2nd IMA Conference on Dense Granular Flows Cambridge, 1-4 July, 2013.

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