Effect Of Sprinkler Riser Height And Cyclic Pressure Head Variation On Water Distribution Pattern For Grid Sprinkler Irrigation Systems

Operating pressure is one of the most important factors in breaking up and dispersion of the water jet into droplets. In addition, the sprinkler riser helps calm, stabilize, and regulate the flow entering from the lateral pipe. The research aims to determine the effect of the sprinkler riser height and the variation of cyclic pressure head on the water distribution pattern for a single sprinkler and their interaction with the spacing and for rectangular and triangular arrangements of sprinklers. The results showed that the water distribution patterns for a single sprinkler operating under constant pressure head and under a cyclically varying pressure head are similar, and the largest differences didn't show a noticeable change in Christiansen's uniformity coefficient (UC). In addition, increasing riser height resulted in water distribution patterns of lower depths with increase in the wetted radius. Moreover, the largest increase in UC appeared in the triangular arrangement and in the lowest pressure head, and the average increase in UC was 8.65%. It was also noted that increasing the pressure head led to distribution pattern of greater depths near the sprinkler, while the pattern tends to stabilize after that. The overall increase in UC under all variables considered is 1.98%, and 70% of the UC values in the rectangular arrangement are greater than or equal to those in the triangular arrangement