Numerical study of geyser events in rainstorm systems at different scales

Considering that we still do not fully understand the behavior of air pockets trapped in rainstorm systems and water flow changes inside pipes, the study of actual geysers presents many challenges. In this study, three-dimensional numerical models were developed to investigate the mechanisms of geyser events triggered by rapid filling flows at different scales. The results showed that, in the first stage of the water–air mixture of the prototype model, a large amount of air was released quickly, and the subsequent overflow lasted for a more extended period. The transport capacity of the downstream pipe, as a critical factor, significantly influenced the water–air interaction of the geyser. Restricting the outlet area and increasing the outlet pressure simultaneously resulted in a stronger geyser. The equivalent density of the water–air mixture increased as the scale decreased during the geyser event.