Abstract:
The irrigation uniformity of sprinkler irrigation system depends on many
design factors such as nozzle diameter, operating pressure and riser height. An
experimental study was conducted to investigate the effect of combination factors of
operating pressure and riser height on water distribution and droplet diameter. To study
the droplet characteristics of the fixed spray plate sprinkler (FSPS), droplet diameter and
velocity was measured using a Thies Clima laser precipitation monitor. Statistical
analysis was conducted on the drop size distribution using volume-weighted method.
The volumetric cumulative frequency of drop diameters permitted to reconstruct water
application along the sprinkler radius in term of the frequency of drops of different
diameters with respect to elevation and working pressure. Wetted diameters and average
application rates increased with the increase in pressure and nozzle elevation within a
distance of less than 2m from the sprinkler. The results showed that various
combinations of the sprinkler could greatly change droplet and water distribution
characteristics. Empirical equations for the water distribution from FSPS were also
developed with coefficients of determination ranging from 95.0% to 99.6%. The study
concluded that the uniformity of a sprinkler irrigation system is more affected by the
combination of distance from sprinkler, riser height and operating pressure
