The present research included studying the effect of the sprinkler nozzle angle and cyclic variation of the operating pressure head on the uniformity of water distribution for many sprinkler heads spacing with rectangular and triangular sprinkler heads arrangement for different sprinkler heads. The research conducted 40 tests to measure a single sprinkler water distribution pattern under similar climatic operating conditions by adopting the water distribution pattern along a beam that represents the radius of the wetting circle which its center is a sprinkler head for different sprinkler nozzle angles (Ɵ + 5 °, Ɵ + 3.5 °, Ɵ, Ɵ -3.5 °, Ɵ -5 °) and the constant-cyclic operating pressure head conditions for different sprinkler heads. 320 patterns were found for field water distribution pattern and uniformity coefficient for four different spacing with a rectangular and triangular sprinkler heads arrangement for the sprinkler heads and the measured water distribution patterns.
The research revealed that 70% of the uniformity coefficients in the rectangular arrangement are greater or equal to its value in a triangular arrangement. The increase in the nozzle angle results in increasing the uniformity coefficient of 1.4% for each degree, an increase in the nozzle angle, and can reach 2.4% for each degree for a specific spacing, arrangement, and sprinkler head. Also, the difference between the two water distribution patterns in the case of operating with constant pressure head and variable pressure head is slight, but it shows in the values of the uniformity coefficient, where the maximum difference reaches 10%, and in general, the best in the values of the uniformity coefficient requires determining the nozzle angle, the spacing and the arrangement of sprinkler head as well as the case of operating pressure head constant or variable.