Simple calculation method of the pressure head distribution along the lateral line in the drip irrigation system.

The main purpose of the design for drip irrigation is uniform application of wat in the field. Usually, the designer examines uniformity of the emitter discharge along the lateral line. For this purpose, it is necessary to calculate the distribution of pressure along the lateral line. However, the calculation of these is generally complex. In this paper, therefore, a simple calculation method of the pressure distribution was proposed. The effects of error in friction factor and the emitter discharge on friction head loss were considered. The results indicated that emitter discharge should be estimated as accurately as possible. Therefore, to decrease the variance of emitter discharge in the whole lateral line, uniform discharge in several segments of the line was used for calculation.The friction factors used were as follows:Re<2000, f=64/Re; Re>2000, f=0.3164 Re, where Re and f are Reynolds number and friction factor, respectively. The putative calculation of pressure distribution proved to be as accurate as that in exactly analysis.