Minimum entropy production in the steady state and radiative transfer

1984 ◽  
Vol 285 ◽  
pp. 279 ◽  
Author(s):  
C. Essex
Keyword(s):  
Steady State ◽  
Radiative Transfer ◽  
Entropy Production ◽  
Minimum Entropy ◽  
Minimum Entropy Production

THE THERMODYNAMIC DESCRIPTION OF HETEROGENEOUS DISSIPATIVE SYSTEMS BY VARIATIONAL METHODS: III. AN APPLICATION OF THE PRINCIPLE OF MINIMUM ENTROPY PRODUCTION TO FLUID DYNAMICS

1964 ◽  
Vol 42 (8) ◽  
pp. 1437-1446 ◽  
Author(s):  
J. S. Kirkaldy
Keyword(s):  
Steady State ◽  
Entropy Production ◽  
Thermodynamic Description ◽  
Free Fall ◽  
Dissipative Systems ◽  
Entropy Production Rate ◽  
Stable Steady State ◽  
Minimum Entropy ◽  
Minimum Entropy Production ◽  
Steady State Rate

The stable free-fall flight of a maple seed gives an exceptionally graphic demonstration of the principle of minimum entropy production. Since the rate of entropy production is proportional to the steady-state rate of loss of potential energy, it is visually obvious that the stable rotary configuration represents a minimum of the entropy production rate relative to an unstable steady-state bomblike trajectory. Regarding this phenomenon as the prototype of many practical steady-state fluid-dynamical systems involving rotational modes, we formally demonstrate the possibility of mathematically defining the stable steady-state configuration by means of this variational principle.

scholarly journals The principle of minimum entropy production and snow structure

2004 ◽  
Vol 50 (170) ◽  
pp. 342-352 ◽  
Author(s):  
Perry Bartelt ◽  
Othmar Buser
Keyword(s):  
Mass Transfer ◽  
Temperature Gradient ◽  
Entropy Production ◽  
Surface Curvature ◽  
The State ◽  
Temperature Gradients ◽  
Curvature Radius ◽  
Minimum Entropy ◽  
Snow Layer ◽  
Minimum Entropy Production

AbstractAn essential problem in snow science is to predict the changing form of ice grains within a snow layer. Present theories are based on the idea that form changes are driven by mass diffusion induced by temperature gradients within the snow cover. This leads to the well-established theory of isothermal- and temperature-gradient metamorphism. Although diffusion theory treats mass transfer, it does not treat the influence of this mass transfer on the form — the curvature radius of the grains and bonds — directly. Empirical relations, based on observations, are additionally required to predict flat or rounded surfaces. In the following, we postulate that metamorphism, the change of ice surface curvature and size, is a process of thermodynamic optimization in which entropy production is minimized. That is, there exists an optimal surface curvature of the ice grains for a given thermodynamic state at which entropy production is stationary. This state is defined by differences in ice and air temperature and vapor pressure across the interfacial boundary layer. The optimal form corresponds to the state of least wasted work, the state of minimum entropy production. We show that temperature gradients produce a thermal non-equilibrium between the ice and air such that, depending on the temperature, flat surfaces are required to mimimize entropy production. When the temperatures of the ice and air are equal, larger curvature radii are found at low temperatures than at high temperatures. Thus, what is known as isothermal metamorphism corresponds to minimum entropy production at equilibrium temperatures, and so-called temperature-gradient metamorphism corresponds to minimum entropy production at none-quilibrium temperatures. The theory is in good agreement with general observations of crystal form development in dry seasonal alpine snow.

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