title: Simulation of counterflow pedestrian dynamics using spheropolygons.
abstract: Pedestrian dynamic models are typically designed for comfortable walking or slightly congested conditions and typically use a single disk or combination of three disks for the shape of a pedestrian. Under crowd conditions, a more accurate pedestrian shape has advantages over the traditional single or three-disks model. We developed a method for simulating pedestrian dynamics in a large dense crowd of spheropolygons adapted to the cross section of the chest and arms of a pedestrian. Our numerical model calculates pedestrian motion from Newton's second law, taking into account viscoelastic contact forces, contact friction, and ground-reaction forces. Ground-reaction torque was taken to arise solely from the pedestrians' orientation toward their preferred destination. Simulations of counterflow pedestrians dynamics in corridors were used to gain insight into a tragic incident at the Madrid Arena pavilion in Spain, where five girls were crushed to death. The incident took place at a Halloween Celebration in 2012, in a long, densely crowded hallway used as entrance and exit at the same time. Our simulations reconstruct the mechanism of clogging in the hallway. The hypothetical case of a total evacuation order was also investigated. The results highlights the importance of the pedestrians' density and the effect of counterflow in the onset of avalanches and clogging and provides an estimation of the number of injuries based on a calculation of the contact-force network between the pedestrians.
authors.affiliation: School of Civil Engineering, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Fernando
authors.initials: F
authors.lastname: Alonso-Marroquín
authors.affiliation: School of Civil Engineering, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Busch
authors.affiliation: School of Civil Engineering, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Coraline
authors.initials: C
authors.lastname: Chiew
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Navarra, 31080 Pamplona, Spain.
authors.forename: Celia
authors.initials: C
authors.lastname: Lozano
authors.affiliation: Departamento de Ingeniería Mecánica, Química y Diseño Industrial, Universidad Politécnica de Madrid, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Ramírez-Gómez