Experimental proof of Faster-is-Slower in systems of frictional particles flowing through constrictions

PASTOR, JOSÉ M.; GARCIMARTÍN, ANGEL; GAGO, PAULA A.; PERALTA, JUAN P.; MARTÍN, CESAR; FERRER, L.M.; MAZA, DIEGO; PARISI DANIEL R.; PUGNALONI, LUIS A.; ZURIGUEL, IKER

PHYSICAL REVIEW E

AMER PHYSICAL SOC

Lugar: New York; Año: 2015 vol. 92

1539-3755

The ``faster-is-slower´´ (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [Helbing D, Farkas I J, Vicsek T, Nature 407:487-490 (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.