- Bejan, A., Constructual theory of organization in nature: dendritic flows, allometric laws and flight,
Design and Nature Comparing Design in Nature with Science and Engineering. First International Conference
pp. 57 - 66 .
(last updated on 2007/04/06)
This paper draws attention to the 1996 constructual theory of the generation of geometric form in flow systems. Flow architecture can be reasoned on the basis of principle: the maximization of global performance subject to finite-size constraints. One example is the generation of tree-shaped flow patterns, as optimized paths between one point (source, sink) and an infinity of points (area, volume). The optimized tree-flow architecture accounts for allometric laws, for example, the proportionality between metabolic rate and body size raised to the power 3/4, and the proportionality between breathing and heart beating times and body size raised to the power 1/4. Another example is the proportionality between the cruising speed of flying bodies (insects, birds, airplanes) and body mass raised to the power 1/6. The "thermodynamics law" status of the constructual principle is discussed