Comparison between the two-component pressure approach and current transient flow solvers

Abstract

Some hydraulic applications are characterized by systems originally flowing in free-surface conditions that subsequently undergo flowregime transition into pressurized flow during rapid filling events. Currently, models simulating these flow regime transitions are classified by approaches that either track the location of the pressurized front or use the Preissmann slot concept. While Preissmann slot models are popular for their overall simplicity, they are limited by the inability to simulate sub-atmospheric, full-pipe flows. Recently, a new model named two-component pressure approach (TPA) overcame this limitation from Preissmann slot models. However, because this new method has not been tested against existing numerical models, this article presents a comparison between the TPA model and three transient flow models. The models are based on the interface-tracking approach, the Preissmann slot concept and a standard closed pipe method of characteristics code. TPA results show good agreement with the results from the models considered in this study.