AN IMPROVED ANALYSIS OF MICROIRRIGATION HYDRAULICS USING A VIRTUAL EMITTER SYSTEM

As the use of microirrigation expands, the need to analyze large syste ms (10,000 emitters or more) becomes more important. The purpose of th is research was to improve the design of large microirrigation systems using the finite element method and the virtual emitter system withou t ignoring minor head losses due to network components. The solution p rocedure involves a second-order partial differential equation that de scribes the flow in a microirrigation system. This equation is solved numerically using the Galerkin's formulation of the finite element met hod. Network components are included in the hydraulic analysis by addi ng their contributions to the nodal equations rather than treating the m as separate elements. Results agreed strongly with those obtained fr om existing pipe-network analysis programs. While some error was intro duced by the virtual node concept, it was small (negligible most often ) and may be reduced further by partitioning each lateral into two or more virtual elements. The proposed method requires less computer time and memory utilization for analyzing a given microirrigation system w hile presenting the accuracy of the hydraulic analysis by incorporatin g the contributions of network components.