1. A normal shock is traveling into still air (14.7 psia and 520°R) at a velocity of 1800ft/sec•
(a) Determine the temperature, pressure, and velocity that exist after passage of the shock wave.
(b) What is the entropy change experienced by the air?
2. The velocity of a certain atomic blast wave has been determined to be approximately 46,000 m/s relative to the ground. Assume that it is moving into still air at 300 K and 1 bar. What static and stagnation temperatures and pressures exist after the blast wave passes? (Hint: You will have to resort to equations, as the table does not cover this Mach number range.)
3. Air flows in a duct, and a valve is quickly closed. A normal shock is observed to propagate back through the duct at a speed of 1010 ft/sec. After the air has been brought to rest, its temperature and pressure are 600°R and 30 psia, respectively. What were the original temperature, pressure and velocity of the air before the valve was closed?
4. Oxygen at 100°F and 20 psia is flowing at 450 ft/sec in a duct. A valve is quickly shut, causing a normal shock to travel back through the duct.
(a) Determine the speed of the traveling shock wave.
(b) What are the temperature and pressure of the oxygen that is brought to rest?
5. A closed tube contains nitrogen at 20°C and a pressure of 1 x 104 N/m2 (Figure P7.5). A shock wave progresses through the tube at a speed of 380 m/s.
(a) Calculate the conditions that exist immediately after the shock wave passes a given point. (The fact that this is inside a tube should not bother you, as it is merely a normal shock moving into a gas at rest.)
(b) When the shock wave hits the end wall, it is reflected back. What are the temperature and pressure of the gas between the wall and the reflected shock? At what speed is the reflected shock traveling? (This is just like the sudden closing of a valve in a duct.)
6. A converging-diverging nozzle has an area ratio of 3.0. The stagnation pressure at the inlet is 8.0 bar and the receiver pressure is 3.5 bar. Assume that y = 1.4.
(a) Compute the critical operating pressure ratios for the nozzle and show that a shock is located within the diverging section.
(b) Compute the Mach number at the outlet.
(c) Compute the shock location (area) and the Mach number before the shock.
7. Nitrogen flows through a converging-diverging nozzle designed to operate at a Mach number of 3.0. If it is subjected to an operating pressure ratio of 0.5:
(a) Determine the Mach number at the exit.
(b) What is the entropy change in the nozzle?
(c) Compute the area ratio at the shock location.
(d) What value of the operating pressure ratio would be required to move the shock to the exit?