Variation of total friction head losses and uniformity coefficients based on inlet pressure head in trickle irrigation laterals

An important objective of any trickle irrigation system is to be obtained approximately a uniform distribution of water delivered through the emitters. In addition, total friction head losses in lateral is an important consideration for optimum design of pressurized irrigation systems. When the required average emitter discharge, the lateral length and inside diameter, characteristics of the orifices are given, then operating inlet pressure head, water application uniformity (uniformity coefficients) and total friction head losses along the lateral can be accurately obtained using personal computers. In this study, a computer program in Visual Basic 6.0 was provided based on the forward — step method for analyzing and designing of trickle irrigation laterals. On the other hand, for different emitter characteristics (y = 0.2, 0.54 and 1.0) and three down slope conditions (S0 = 0.00, 0.02, and 0.05) for a lateral length, and inside diameter the inlet pressure head effects on the water application uniformity, total friction head losses and residual outflow at the downstream end of lateral were analyzed and evaluated graphically in dimensionless form for a practical purpose. For different design applications, the results of used stepwise calculation method has the higher accuracy rather than the results of other analytical and numerical methods.