Emergence of design is physics: a constructal view of pedestrian dynamics, collective motion and synchronization.

Abstract

The idea of emergence grounds and gives meaning to biological phenomena. It is underlying all phenomena far from equilibrium and is essential in physics. Another important concept linked to emergence, from the perspective of complexity, is self-organization that is widespread in biological systems, including cells, organisms, and groups. Self-organization leads to emergent properties, meaning that the whole system has characteristics that differ qualitatively from those of the component parts without the interactions. Given that this decentralized control is widespread, the question comes forth of why this is the case. The constructal law of Adrian Bejan puts forth the idea that the emergence of configuration (design, patterns, shape) is a physics phenomenon. Nonequilibrium systems morph freely toward configurations that allow all its currents to flow more easily over time. Here, we address the emergence of design in pedestrian flows (i.e., far from equilibrium dissipative systems) from the viewpoint of the constructal law. Particular attention is paid to the dynamics of walking and running forms of human gait, the properties of transitions between these two forms of locomotion, and the rich variety of self-organized collective behaviors in a crowd of pedestrians.