Abstract
The hydrodynamic problem of defining the velocity profile of liquid is resolved, assuming for the liquid density to be compressed in accordance with exponential law along coordinate z. The continuity equation for this liquid is concluded. Influence of barometric index λ on motion character is estimated. Flowrate decrease and coefficient of hydraulic losses for the compressed liquid are found. Principle of quasi - isothermal approximation is established, and the effect of temperature gradient on final result is qualitatively considered.