Effect of nonuniform conduit section on waterhammer

Fundamental equations for studying transient flows in conduits with variable cross sections are reviewed. The flow is assumed to be quasi-one-dimensional provided the variation in the pipe cross section is mild. The set of equations is then integrated by a numerically implemented characteristics method. A benchmark case is investigated through which the effect of contraction and expansion of pipe cross section on the waterhammer phenomenon (pressure surge) is addressed and discussed. The result shows a shift of pressure fluctuation from low frequency mode to high frequency mode as the pipe alters from a necking to a bulging configuration.