True or False: In the case of an adiabatic choked flow through a long pipe, the gas exiting the pipe makes an abrupt change from Pchoked to the ambient pressure.

True or False: In the case of an adiabatic choked flow through a long pipe, the gas exiting the pipe makes an abrupt change from Pchoked to the ambient pressure.

• A. Not Applicable
• B. It Depends
• C. False
• D. True

Answer: (D)

In adiabatic choked flow, the flow becomes sonic at the choke point, which fixes the pressure there (the critical or Pchoked pressure) regardless of the downstream conditions. When the gas exits the pipe into ambient, the jet must match the ambient pressure, so the pressure at the outlet docks to the ambient value. Because the throat is sonic, information cannot travel upstream to adjust the interior flow, so the transition from the fixed Pchoked inside to ambient pressure outside happens essentially at the outlet, appearing as an abrupt change. That is why the statement is true: the exit pressure rapidly drops from the choked value to ambient at the discharge.

In adiabatic choked flow, the flow becomes sonic at the choke point, which fixes the pressure there (the critical or Pchoked pressure) regardless of the downstream conditions. When the gas exits the pipe into ambient, the jet must match the ambient pressure, so the pressure at the outlet docks to the ambient value. Because the throat is sonic, information cannot travel upstream to adjust the interior flow, so the transition from the fixed Pchoked inside to ambient pressure outside happens essentially at the outlet, appearing as an abrupt change. That is why the statement is true: the exit pressure rapidly drops from the choked value to ambient at the discharge.