Parametric Study of Perforated Pipe Underdrains Surrounded by Loose Aggregate

Abstract

AbstractA detailed computational parametric study of a perforated pipe underdrain surrounded by loose aggregate has been conducted. Several controlling geometric parameters (i.e., trench width, head, aggregate depth over the pipe, pipe wall perforation area per unit length of pipe, and the area of individual perforations) were considered and the variation of pipe discharge characteristics as a function of these parameters has been quantified. Results indicate that, for each combination of these parameters, there is a finite pipe length after which discharge does not increase with increasing pipe length. This pipe length depends on the pipe wall perforation area per unit length of pipe, pipe cross-sectional area, and losses associated with them. It was found that the effective pipe system discharge coefficient is independent of the channel width, aggregate depth, and head over the pipe for the range of parameters tested. The computational fluid dynamics (CFD) results were used to develop an equation for th...