A two-directional calculation model for the combination uniformity coefficient of an impact sprinkler

An impact sprinkler loaded on a remote control trailer can be used for motion to improve the efficiency of a single Hard Hose Traveler in small and medium-sized irregular fields. Herein, a model for calculating the combination uniformity coefficient (CU) was established in the square test area under two-directional motion. The accuracy of the irrigation uniformity model was verified using the test data of application depth (h(n)). The results revealed that the nozzle diameter, speed of sprinkler motion (v), and motion methods can significantly impact the average application depth ((h) over bar) and the CU value of sprinkler irrigation performance. The motion methods included uniform motion and a constant speed combination motion. The highest CU values were recorded when the primary and secondary nozzle diameters were 10.5 and 4.5 mm, respectively (overall value, about 81.7%). The CU value gradually decreased with the increasing v value of the sprinkler. The CU value was higher under the constant speed combination motion than the uniform motion. The (h) over bar value gradually decreased with increasing v value. The (h) over bar value was classified based on the water requirement of different crops. The optimal CU value corresponding to each grade of the (h) over bar value was obtained in different schemes of the combination of sprinkler speeds. This research guides the realization of variable spraying of a Hard Hose Traveler and the intelligent uniform motion of the sprinklers.