 If initial values of "s""i" and "M""i" are defined, a new equation for dimensionless entropy versus Mach number can be defined for each model.These equations are shown below for Fanno and Rayleigh flow, respectively.Figure 5 shows the Fanno and Rayleigh lines intersecting with each other for initial conditions of "s""i" = 0 and "M""i" = 3.