"For a finite-size system to persist in time (to live), it must evolve in such a way that it provides easier access to the imposed currents that flow through it."
Constructal law is the non written law of nature, the tendency in any flow system to reach the maximum performance. From this point of view, constructal theory is a complimentary to second law of thermodynamics. As the second law of thermodynamics predicts the direction of events, shape generation is not provided by it. For example, a river has a pathway which goes through it. Second law predicts that a river runs from higher altitudes to lower altitudes but it does not tell us the shape of the river.
Invoking constructal theory is not as simple as its statement. Worth to mention that, Constructal law is not an optimizing algorithm like genetic algorithm. Thus, there is no direct mathematical procedure which can be used to predict the shape of the flow systems with it, and this means that each specific problem needs its specific solution.
Any flow system has some degrees of freedom for its shape change and based on constructal law, if we provide it all the freedom needed; it will change in time until it reaches its maximum global performance. This trend is somehow an evolvement from simple to complex through time and that’s a trend which is used in nature in the whole passed time.
Based on what stated above, for any problem which is going to be represented in this frame, degrees of freedom should be identified and after that, global performance versus these degrees of freedom will have an optimum point which is the best. This means that if the system wants to evolve in a natural manner, from any point it starts it will change in time until it reaches this optimum point.
An example can present the idea better:
Consider it is supposed to distribute water from point A to points B and C, and this distribution is done by a Y junction. If all the degrees of freedom constrained except for the split place, (namely L1) where the best place for the split is? Constructal theory says, if we give the freedom in certain directions to such a flow system, it (here L1) will morph to its optimum point of performance.
One may say, ok! What is the difference between constructal theory and a simple search for an optimum configuration? Simply the answer is nothing but the constraints under which we find this best configuration. There are two global constraints: (1) the total construct volume and (2) the total space (area) occupied by the construct.
Under the above constraints, we give certain degrees of freedom to the configuration to find the optimum point of performance. These degrees of freedom are applied to the flow system by means of analytical, numerical or even experimental investigations.
After all, freedom to morph versus the performance makes the shape.
For more information go to www.constructal.org
For more information go to www.constructal.org