Question: Air is expanded from a large reservoir in which the pressure and temperature are 300 kPa and 20°C, respectively, through a convergent-divergent nozzle, which gives an exit Mach number of 1.5. The air from the nozzle flows down a 5-cmdiameter pipe to a reservoir in which the pressure is 140 kPa. A normal shock wave occurs at the end of the pipe. Find the length of the pipe. Discuss what will occur if the pressure in the reservoir at the discharge end of the pipe is decreased. The flow in the nozzle can be assumed to be isentropic and that in the pipe can be assumed to be adiabatic. The friction factor in the pipe can be assumed to be 0.002.