long pipeline

Unsteady processes of isothermal natural gas flow, emerging in a long pipeline when there is switching-over from one stationary process to another stationary process, have been considered in this paper.  The one-dimensional system of gas dynamics equations is used for that purpose.  It includes equations for conservation of mass and momentum written relative to of dimensionless mass and flow densities.  Three boundary-value problems formulated for this system define three models for control of the transient processes.  The problems differ by the boundary (control) functions imposed at the e