EXERGIC ANALYSIS AND VARIATIONAL INEQUALITIES METHODS IN SOME FLUID MECHANIC’S PROBLEMS

Abstract

Purpose. The foundations of the energetic approach for analyzing of the bodies with dissipation properties are presented in the article. Methodology. Energy resource of arbitrary body is characterized by the sum of the exergy and anergy. The first of them indicates the part of energy which can be used to perform mechanical work. The second – is a measure of the processes’ irreversibility in the interaction of such body with the others. It indicates what part of the energy dissipates into the environment as low-temperature heat and can’t be used for the mechanical work performance. The energy balance in the thermodynamic systems is the basis for the relevant variation principles formulation. The introduction of the exergy and anergy concept leads to the variation inequalities formulation. They are transformed into equality in almost non-realized case of the reverse ability and equilibrium process, or in the case of the limit equilibrium state. Conclusion. Variation inequalities can be used for the formulation of general relations, which determine the parameters of quasi-static flow of real fluid in its interaction with solid obstacles - wetted perimeter of pipe or open channel, as well as the inclusions - in the cases of unknown interaction surface. These problems in particular arise in the analysis of the erosion process and shoreline destruction it caused, river flow interaction with stones during floods in natural streams.