evaluation of operational charachteristics of spray sprinklers equipped with various deflector pads

the variety of sprinkler devices available for the center pivot and linear irrigation systems has been increased dramatically in recent years. in the current study, via conducting some indoor experiments, one type of fixed pad spray sprinkler (d3000) and two types of moving pad spray sprinklers (r3000 and s3000) with various configurations (working pressure, nozzle size and type of deflector pad) were comprised to evaluate discharge-pressure relations, wetted diameter, and average application rate. as well as, using field test data of distribution pattern of r3000 sprinkler in various wind speeds and directions, the effects of wind on the varying of wetted diameter were evaluated. experimental equations for predicting wetted diameter in no-wind conditions in addition to nozzle sizing equation for hydraulic design of center pivot system were presented. predicted wetted diameters of no-wind conditions were compared with observed values that were not used in developing experimental equations so r2 and rmse values of validation data were between 0.68-0.88 and 0.83-1.64 m, respectively that shows relatively good accuracy of proposed equations. experimental coefficient of c as a function of the wind velocity introduced for prediction of the wetted diameter of the sprinkler affected by wind. comparison of the predicted wetted diameters using the coefficient of c with observed values in the field conditions showed that proposed equation with r2 of 0.66 and rmse of 1.27 m have relatively more accuracy than kincaid (13) equation.