Sector Angle Effects on Raingun Application Uniformity.
1993
Husein Mohamed
The effect of sector angles 270 and 240 degrees on application uniformity of Sykes Hose-Reel 180/50 Irrigator under various wind conditions coming from behind the raingun parallel to travel lane were investigated. The result were compared with the performance of the machine when the sprinkler head rotates full circle (360 degrees). Christiansen Coefficient of Uniformity is a measurable index expressed as a percentage to show the degree of water distribution uniformity obtainable for any size sprinkler operating under given conditions. It is obtainable for any size sprinkler operating under given conditions. It is affected by the pressure-nozzle relations, sector angles, sprinkler spacing, and wind conditions. The Significance of coefficient on uniformity is to indicate whether a farm land is uniformly, under, or over irrigated which affect both the quality and total yield produced. Stationary patterns were used to simulate water distribution of the travelling raingun. These values were overlapped at lane spacing of 24 to 44 in steps of 4 m. Computer contour graphics and digital simulations were used to analyze the stationary and travelling gun wetting patterns, respectively. At 'no' and 'low' wind conditions, all the three sector angles tend to form 'doughnut' or circular wetting patterns with uniform depth of water application at constant radial distance from sprinkler head. At medium wind their wetting surface area decreases as the wind speed increases. For all the three sector angles, coefficient of uniformity and mean application depth decreased as the lane spacings increased for the same wind speed. Sprinkler are setting of 360 degrees gave better uniformities for all the lane spacings considered than either 270 or 240 degrees sector angles for wind parallel to travel lane in the range of 0.18-3.00 m s** (-1).
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