New approach to deriving gas dynamics equations

Abstract

We derive the gas dynamics equations considering changes of velocity distribution function on the scale of a molecule free path. We define the molecule velocity distribution function in a specific form so that only molecule velocities after intermolecular collisions in a chosen fixed volume are taken into account. The obtained equations differ from the well-known Navier-Stoks equations and contain the new terms. The continuity equation includes the second derivatives of dynamical viscosity. The equation of momentum conservation does not include the volume viscosity and the equation of energy conservation describes the transformation of gas mass velocity into the gas thermal energy. One can expect that these new equations of motion allow to construct a description of macroscopic physical phenomena in more complicated situations than the standard gas dynamics equations do.