Prediction of leakage flow rate from upward water jets bursting at the ground

Abstract This paper presents experimental studies to explore the behavior of upward water jets in granular beds. The test conditions included both the cavity and chimney regime. Combining our results with data available in the literature, it was possible to fit a linear relationship to describe the dimensionless upward water velocity at the bed surface (u/U) as a function of kFr, in which Fr is the Froude number and k is a fitting parameter that was linearly related with the medium particle diameter d. A threshold condition (kFr = 1) was also proposed to predict the onset of the chimney regime, which was consistent with published data. Finally, a simple equation based on d, D and H was derived to predict the real-scale leakage flow rate Q from upward water jets bursting at the ground. The results obtained will potentially help water utilities estimate the water loss from underground pipelines.