Chapter 3 – What Causes Surge?
Surge Analysis and the Wave Plan Method
Supplementary Material: Example Problems and Solutions
Chapter 3 – Problem 3.8
3.8 Consider the following simple pipeline system where L is length of pipeline between the two dominant boundaries (a reservoir at one end a valve at the other end) and c is the celerity.
a. What is the corresponding wave period?
b. Compute the wave period if L = 2000m, and c = 1000 m/s.
c. Calculate the steady state flowrate if the valve is fully open, the depth of water in the reservoir is 20m, and the wide-open valve resistance is 10. The pipe internal diameter = 300 mm, and the D-W pipe friction factor is 0.02. [Answer: Q=0.1393 m3/s, V=1.971 m/s].
d. If the valve is closed instantaneously, what is the Joukowsky’s pressure rise on the inlet side of the valve? [Answer: 200.9m].
e. Would the total rise in pressure at the inlet side of the valve be the same as that computed in part d if the valve is closed in (i) 0.1s, (ii) 0.5s, (iii) 1.0s, (iv) 2.0s, 5.0s, and (v) 10.0s?
f. What is the shortest valve closure time to avoid the full Joukowsky pressure rise (resulting from the total change in velocity irrespective of the time of closure) at the inlet side of the valve?
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