Talk:Constructal theory

message: Could someone with a more in-depth understanding of the domains at work here include some more detailed examples? The current text gives the flavor of what I envision this to be, but I still don't really understand it. Skorgu 22:40, 9 February 2006 (UTC)
replies: text: Actually, that would be the method of applying constructal theory in engineering. The principle appears in the text: allowing currents to flow easier from source to sink. The diffrerent patterns obtained depend on the geometry of the source and the sink (point, linear, surface, volume sources and sinks) and from the dual nature of the medium between them: there may be a "porous" medium with very little flow or there may be a "channel" with very high flow. In nature, "channels" appear in the "porous" medium due to the tendency of flow to occur with less resistance. Ferred 10:56, 17 August 2007 (UTC)

message: this sounds similiar to Stuart_Kauffman's and others in the field of Complex_systems ideas about the role of Self-organization in evolution and biology, and Ilya_Prigogine's ideas on Dissipative_structures in Non-equilibrium_thermodynamics. Kevin Baastalk 17:16, 12 January 2011 (UTC)
thread_title:  related pages? 

message: Wikipedia is an encyclopedia. As such it is purely descriptive. Thanks to wikipedia I now know what constructal theory claims to be. However my problem is that I just don't believe this principle is valid. It doesn't seem to work even in fluid dynamics which the language suggests should be the field it most directly applies to. 
Consider a simple case of a fluid flowing through a pipe. Constructal theory would suggest that the fluid should organise its flow in a fashion to optimize throughput. OK - the water flows through the pipe. But now start increasing the pressure difference across the pipe. The flow rate will increase for a while, but at a certain pressure the flow rate will suddenly and drastically decline. This point is called the onset of turbulence. Once turbulence ensues the flow pattern becomes chaotic and the pipe is able to sustain only a much reduced rate of flow. This change happens spontaneously and seems to violate the constructal law. 
Or consider meanders in river systems. If the objective is to maximise flow then a nice straight channel would seem to be the ticket. But straight channels are unstable and a river will instead carve out a pattern of meanders which are highly inefficient in terms of maximising throughput. 
So is this a problem for Wikipedia? Not necessarily. An encyclopedia isn't an arbiter of correctness, for example the Flat Earth theory has a page. However perhaps my understanding of the law obtained by reading the main page is deficient, in which case a better explanation might be required. If my understanding is correct then in my opinion the constructal law is absolute twaddle. Hawthorn (talk)  —Preceding undated comment added 02:01, 28 March 2012 (UTC)
thread_title:  Don't believe it 

message: To merge the Wikipedia’s entry on Constructal Law with the entry on “Maximum Power” would be inappropriate because the Constructal Law is a law of physics, while “Maximum Power” is not a principle:
# “Maximum Power” was discredited on irrefutable thermodynamics grounds by the well known MIT thermodynamics professor Elias Gyftopoulos E. P. Gyftopoulos, On the Curzon-Alborn efficiency and its lack of connection to power producing processes, Energy Conversion and Management, Vol. 43, 2002, pp. 609-615. There is no evidence of “maximum power” design anywhere.
# The maximization of power output per unit of fuel or food consumed is entirely different concept.  It is an optimality statement known in biology and engineering as Entropy Generation Minimization (EGM), (e.g., A. Bejan, Advanced Engineering Thermodynamics, 3rd ed. Hoboken: Wiley, 2006).
EGM is one of more than 10 statements of optimality (static, end design, destiny), which, at best, have local (ad hoc) applicability, and which contradict other ad hoc statements such as maximum entropy production.  The growing literature shows that the evolutionary design phenomenon summarized as the Constructal Law accounts for all the ad hoc and contradictory statements that are in use, for example, minimum flow resistance versus maximum flow resistance.  This why the Constructal Law is a law of physics, the law of evolutionary design in nature. For a review of this unification, see:  A. Bejan and S. Lorente, The Constructal Law and the Evolution of Design in Nature, Physics of Life Reviews, Vol. 8, 2011, pp. 209-240.  Mre env (talk) 01:49, 7 March 2013 (UTC)
thread_title:  On the suggestion to merge the Constructal Law and the maximum power “principle”