Pressure Pulsations in Flow Through Branched Pipes

Pronounced cyclic variations in pressure and in flow into opposing laterals from a common pipe or conduit have been observed in several widely different and independent pipe systems. In one instance, noise operation of two centrifugal pumps was encountered where the suction pipes were joined in a common intake line. Unsteady flow also has been observed in the last two ports of a symmetrical manifold on a lock filling system. In one interesting case, fluctuations in the heights of flames on a pair of gas burners operating from a common supply pipe were reported. Unsatisfactory registration of two flow meters operating in parallel on a cross-county pipeline is believed to be a result of the same phenomenon of fluctation of flow. The only published reference found on the unstable flow in laterals was in a report of extensive experiments on manifold flows conducted under the direction of John S. McNown at the Iowa Institute of Hydraulic Research. A great difference in loss through single and double laterals was observed, and the presence of fluctuations was noted but not investigated. Lastly, intensive vibrations of loading rigs delivering gasoline to more than noe barge at a waterfront header supplied by one central pipe can be cited as an undesirable consequence of the pulsations generated at symmetrical laterals on pipelines. The question of the cause of pulsations appeared to be of sufficient practical importance to warrant its study as graduate thesis projects at the University of Kansas.