Mechanics of Secondary Water-Hammer Waves

Abstract

While tests were being carried out on the motion which follows sudden closure of a valve at the beginning of a pipe, certain irregularities of the ensuing wave trains were noticed. Such irregularities were brought out all the more clearly because a sensitive electronic recorder was used. The special experimental arrangement prevented the appearance of these irregularities, henceforth called secondary waves, during the first surge, which helped considerably the theoretical exposition. However, they were later superimposed on both the negative and positive surges. The reasons, which are not entirely different in both instances, are the main subject of discussion in this paper.

Water hammer with column separation: A historical review

“…Some of O'Neill's (1959) analytical examples exhibited short-duration pressure peaks, but his experimental pressure records did not. Gayed and Kamel (1959) clearly explained the occurrence of short-duration peaks and they claimed their appearance in one of the measurements ( Fig. 11(a) in their paper).…”

“…Friction loss resulted in damping and the mean value of head rise decreased with every cycle, as did the size of the cavity. Gayed and Kamel's (1959) analysis included variable-length rigid-column theory and water-hammer theory with noninstantaneous excitation. Kephart and Davis (1961) used rigid-column theory to determine the magnitude of the pressure rise when liquid columns rejoined in pump discharge lines equipped with check valves at the pump outlet.…”

“…Lupton (1953), in discussing Binnie and Thackrah's (1951) paper, did not agree with the use of air valves because of the unpredictably high pressures that may result from the presence of air in a pipeline. Gayed and Kamel (1959) showed pressure histories obtained in a 2.6 m long pipe for different initial flow velocities. Hagler (1964, 1966) considered water hammer in a pipeline transporting phosphate-ore slurry.…”