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Viscosity coefficient of a neutral gas at atmospheric pressure, high pressure and in the liquid state with help of the FS kinetic equation and a new hypothesis of irreversibility.

Viscosité d'un gaz neutre à pression atmosphérique, dense et liquide déterminée à l'aide de l'équation cinétique FS et une nouvelle hypothèse d'irréversibilité.

Abstract : The calculations of the viscosity coefficient of a gas become very complicated when the density of particles increases.
These calculations become very complicate because of the possibility of occurrence of more than two particles collisions. But the hypothesis of the “molecular chaos” cannot always be valid and the correlations between the particles become more important with increasing density.
The introduction of a micro-irreversibility process in the collision between two particles compatible with the H-theorem, cannot assure the definition of the band of dissipation on the basis of dynamics and statistical models. We need the theory of the intermolecular forces and the electromagnetic theory.
In order to overcome this difficulty, we define by simulation a relation between the relaxation of the pair distribution function and the collision time of two particles. In this way, we get a band of dissipation in the attractive part of a realistic potential as Lennard-Jones or Hanley-Klein potential. It is the space where the acceleration variations are negative