Friction Head Loss in Center-Pivot Laterals with Single Diameter and Multidiameter

Abstract

In this paper, efficient closed form expressions to compute the friction head loss in center-pivot laterals using the method of the discrete outflow distribution are presented. The results are applicable to center-pivot systems with single diameter and multidiameter, with constant spacing between sprinklers along the lateral, with and without end gun sprinklers, and with and without closed outlets at the beginning of the lateral. The head loss between the last outlet and the end gun, usually neglected in the existing literature, is explicitly considered. The values of the friction head loss along the lateral obtained with the discrete outflow distribution are compared with those obtained with the continuous outflow distribution and with other expressions available in the literature. The proposed expressions provide a more general description of head loss and lead to more accurate results.