Evaluation of water distribution and uniformity of sprinkler irrigation based on harmonic analysis and finite element method

Abstract

A model that describes the water distribution of a single fixed spray plate sprinkler (FSPS) based on the harmonic analysis was proposed. The relationship between the pressure head, nozzle diameter, mean sprinkler irrigation depth, and amplitude was established. An analytical model for evaluating the sprinkler irrigation uniformity coefficient of a multi-sprinkler combination was developed by introducing a weighting coefficient. In conjunction with the sprinkler irrigation system's finite element hydraulic calculation model, the impact of the pipe diameter, sprinkler number, and sprinkler spacing on system energy loss, pressure head, and sprinkler irrigation system uniformity was assessed. The results demonstrated that under varying pressures and nozzle diameters, the Camargo and Sentelhas coefficient (c) between the measured and fitted mean value of the sprinkler irrigation depth of a single FSPS was greater than 0.99, while the c between the measured and fitted amplitude value was approximately 0.93. Under different combinations of nozzle, pressure head, and sprinkler spacings, the measured, derived, and calculated values of 54 sprinkler irrigation uniformity combinations were basically consistent. The uniformity of the combined FSPS under a linear-move sprinkler system was significantly affected by nozzle diameter, pipe diameter, sprinkler spacing, and inlet pressure head at 0.01 level. The number of sprinklers also had a significant impact at 0.05 level. The findings of this study could serve as a theoretical foundation for the proper design of linear-move sprinkler irrigation systems.