Vascular flow design and predicting evolution

Porous materials are usually thought of as amorphous mixtures of two or more things, solids, fluids, and voids. I was drawn to the nature absent from the amorphous: the structure, flow, configuration, design, purpose, and evolution. This article is a pictorial review of the work. It begins with defining the terms: design, freedom, evolution, and prediction (theory). Vascular (tree shaped) architectures offer greater flow access than channels with only one length scale (diameter, slit, wall to wall spacing). The tendency to evolve with freedom toward flow configurations that provide greater access is everywhere in nature, bio, and non-bio. This universal phenomenon is summarized as the Constructal Law of evolution everywhere, which empowers us to predict evolution, miniaturization, high density of fluid flow and heat transfer, and scaling up (or down) of existing designs. Vascular designs are icons of the multiscale design called hierarchy. Vasculatures occur naturally because they flow more easily—they offer greater access—than one-scale designs. All movement in society is hierarchical, from city traffic to global air traffic, fuel consumption, and wealth. The future of evolutionary design everywhere points toward vascular, hierarchical flow architectures that will continue to morph with freedom and directionality.