A 250 m long steel pipe issues from a reservoir as shown in Figure P8.50. The pipe runs horizontally with a diameter of 0.5 m and 20 mm wall thickness. The discharge in the pipe is 1  /s. The water...

A 250 m long steel pipe issues from a reservoir as shown in Figure P8.50. The pipe runs horizontally with a diameter of 0.5 m and 20 mm wall thickness. The discharge in the pipe is 1
 /s. The water surface in the reservoir is 50 m above the pipe outlet as shown and the temperature is 20°C.

a. If a valve is located at the end of the line, what is the minimum closure time in order to avoid a maximum pressure surge?

b. If the valve is closed faster than the time computed in part (a), what will be the maximum pressure that will develop in the line?

c. If the valve is closed in twice the time computed in part (a), what pressure surge will develop in the line?