Measurements of Mixed Transient Flows

Abstract

Laboratory experiments were carried out to observe the mechanism of transition between free‐surface flow and pressurized flow conditions in a circular pipe. Filling or pressurization of a pipe is typically accomplished by a positive surge moving toward the free‐surface flow region. Under certain conditions airwater interaction during pressurization can produce water hammer pressures. Draining or depressurization also produces a shock surface, i.e. a negative surge, that moves toward the pressurized zone. Unlike the positive surge, the negative surge produces negative pressure in the pressurized zone. Some aspects of the transition between positive and negative surges were also studied.