Correction factors for sprinkler laterals

Irrigation laterals are unique pipelines as there is a decrease of flow along the pipeline. This makes the hydraulics of laterals an interesting problem.Laterals can be broadly classified into two categories: a) Laterals where the flow decreases in direct proportion to the length of the lateral (linear variation). This is typical of sprinkler systems with fixed, periodic move or linear displacement laterals; b) Laterals where the flow decreases in proportion to the square of the length of the lateral (non-linear variation). This is typical of center-pivots.Although it is conceptually feasible to have a variety of functions relating discharge along a lateral to length, non-linear variation in lateral discharge, other than (b) above, have no practical application and are not considered further.The friction correction factor F can only be applied to pipelines of a single diameter and without outflow i.e flow at the downstream end of the lateral. The first section of this thesis presents a new friction correction factor G. Factor G can be applied to laterals with outlets and downstream outflow. The second section in this thesis develops the adjusted friction correction factor Ga. This is analogous to the adjusted friction factor Fa although Ga can be applied to laterals with downstream outflow. In section three, average correction factors FAVG and GAVG are developed. Section four extends these concepts to develop adjusted average correction factors; FaAVG and GaAVG. Average correction factor GaAVG is demonstrated as a generic average correction factor.Section five of this thesis re-examines the earlier work on friction factors for center-pivots. A new conceptual model is proposed. New friction correction factors are developed which are dependent on number of outlets and the friction equation used. The final section develops new correction factors for head loss caused by friction and pressure head distribution in center pivots with end guns using the concept of end gun ratio.