Bewässerungs- und Entwässerungssystemtechnik

A software for simulating the hydraulics of linear-move and center-pivot irrigation systems, LincSys, is presented in the current paper. This manuscript is part II of a two-part paper. Descriptions of software functionalities relating to the graphical user interface and the hydraulic simulation module of LincSys are presented in manuscript I. Results of evaluation of the computational module are summarized and a set of application examples are presented here. A limited evaluation of the hydraulic simulation module suggests that the predictive capability of the model is satisfactory. In line with results of earlier studies, computed outputs of application examples show that the lateral pressure profiles of linear-move and center-pivot systems exhibit both local span-scale spatial variability patterns and broader inter-span trends, suggesting that a complete description of the pressure profile patterns of these laterals requires that both spatial variability attributes be assessed. While the lateral pressure spatial variability properties are primarily functions of span geometry, the outcomes of the current study confirm results from an earlier study that field slope and lateral diameter can modify the basic effects produced by span geometry. Simulated emitter discharge profiles indicate that distribution uniformity along linear-move and center-pivot laterals can be high. The results also show that, depending on the system configuration option, the spatial variability attributes of an emitter discharge profile can have similarity with certain aspects of (or can be completely different from) that of the corresponding lateral pressure profile.

LincSys is a software for simulating the hydraulics of linear-move and center-pivot irrigation systems. The term LincSys is a mnemonic for the phrase ‘linear-move and center-pivot systems’. The LincSys software is comprised of a pair of executable files: a hydraulic simulation module, HydrSimLaterals.exe, and a graphical user interface (GUI), LincSys.exe, through which the user interacts with the hydraulic module. The user interface and the computational module are coupled through an application programming interface. The simulation module of LincSys is based on a numerical solution of the continuity and energy balance equations for one-dimensional steady pipe flow. The model can simulate the hydraulics of linear-move and center-pivot systems that use the following emission devices to meter outlet discharges along the lateral: (i) drop-tubes fitted with pressure reducing valve and emitter assemblies, (ii) drop-tube and emitter assemblies, or (iii) emitters placed directly on lateral outlet ports. The GUI of LincSys consists of a tabbed form with four windows, namely, the Systems-Projects, Input, Output, and Charts tabpages. Each tabpage provides access to a subset of the program functionalities, consisting of: project management, help utilities, displaying and enabling the editing of input data, conducting simulation, and displaying output data and charts. LincSys employs a mix of standard Windows user interface controls to enable users to issue commands, navigate the user interface, and access program functionalities. Note that this manuscript is part I of a two-part paper and it describes the hydraulic simulation module and the GUI of LincSys. Part II presents application examples and a brief summary of results of model evaluation.