MODELING ENTROPY AND EXERGY CHANGES DURING A FLUID SELF-ORGANIZATION PROCESS

The possibility and the need to describe a complex system behaviour by means of functions of state variables is stressed here, yielding a de tailed calculation of exergy and entropy changes within a fluid model, according to input flows of available resources. This 'from within' a pproach is presented as an applied example of our previous claims (Ulg iati, S., Bianciardi, C., 1997. Ecol. Model. 96, 75-89) about the rele vance of measures of far-from-equilibrium states based on internal and physically measurable state variables. The system model evolution to a thermodynamic equilibrium state is described, through different cond uction, convection and chaos phases. Transition from conduction to con vection is carefully investigated. Results are compared with literatur e 'from outside' descriptions based on assumed links between internal organization and input flows from outside. (C) 1998 Elsevier Science B .V. All rights reserved.