On the One-Dimensional Theory of Steady Compressible Fluid Flow in Ducts with Friction and Heat Addition

Steady, diabatic (non‐adiabatic), frictional, variable‐area flow of a compressible fluid is treated in differential form on the basis of the one‐dimensional approximation. The basic equations are first stated in terms of pressure, temperature, density, and velocity of the fluid. Considerable simplification and unification of the equations is then achieved by choosing the square of the local Mach number as one of the variables to describe the flow.The transformed system of equations thus obtained is first examined with regard to the existence of a solution. It is shown that, in general, a solution exists whose calculation requires knowledge only of the variation with position of any three of the dependent variables of the system. The direction of change of the flow variables can be obtained directly from the transformed equations without integration. As examples of this application of the equations, the direction of change of the flow variables is determined for two special flows.In the particular case whe...