Compressible pipe flow with friction, Sec. 9.7, assumes constant stagnation enthalpy and mass flow but variable momentum. Such a flow is often called Fanno flow, and a line representing all possible property changes on a temperature-entropy chart is called a Fanno line. Assuming an ideal gas with k = 1.4 and the data of Prob. 9.86, draw a Fanno line for a range of velocities from very low (Ma 1) to very high (MA 1). Comment on the meaning of the maximum-entropy point on this curve.