Spontaneous emergence of counterclockwise vortex motion in assemblies of pedestrians roaming within an enclosure

Iñaki Echeverria (1) , Alexandre Nicolas (2) , Raúl Cruz Hidalgo (1) , Angel Garcimartin (1) , Iker Zuriguel (1)

1 UNAV - Universidad de Navarra [Pamplona]
2 iLM - MMCI - iLM - Modélisation de la matière condensée et des interfaces

The emergence of coherent vortices has been observed in a wide variety of many‑body systems such as animal flocks, bacteria, colloids, vibrated granular materials or human crowds. Here, we experimentally demonstrate that pedestrians roaming within an enclosure also form vortex‑like patterns which, intriguingly, only rotate counterclockwise. By implementing simple numerical simulations, we evidence that the development of swirls in many‑particle systems can be described as a phase transition in which both the density of agents and their dissipative interactions with the boundaries play a determinant role. Also, for the specific case of pedestrians, we show that the preference of right‑handed people (the majority in our experiments) to turn leftwards when facing a wall is the symmetry breaking mechanism needed to trigger the global counterclockwise rotation observed.

Mots clés: pedestrian crowd; pedestrian modelling; vortex

Domaines: Mécanique statistique [cond-mat.stat-mech]; Psychologie

Iñaki Echeverria, Alexandre Nicolas, Raúl Cruz Hidalgo, Angel Garcimartin, Iker Zuriguel. Spontaneous emergence of counterclockwise vortex motion in assemblies of pedestrians roaming within an enclosure. Scientific Reports, 2022, 12, pp.2647. ⟨10.1038/s41598-022-06493-0⟩. ⟨hal-03367854⟩