Some special features of description of thermal and dynamic processes in gases in the approximation of homobaricity

The ranges of validity of approximation of homobaricity are analyzed from the standpoint of the law of conservation of energy. A mathematical model is suggested for one-dimensional unsteady-state problems allowing for the assumption of homobaricity, which is based on separating the calculation of density and pressure from the calculation of velocity and temperature. The formulation of the model admits of different types of symmetry of the problem and presumes that the boundaries of the region may be movable and permeable to heat and mass. The correlation between the approximation of homobaricity and the thermody-namic description of processes is analyzed.