UkrainianProfessional Education

Abstract

The analysis literature devoted to the calculation of hydrotechnical structures showed that there are recommendations that take into account the influence roughness of the channel on the value of the transformation of the transit flow of liquid with steady movement along the length of the channel. But it is difficult to apply them for reclamation systems, which include complexes of hydrotechnical and transport structures that create additional resistance to water movement, as a result of which the movement of water in the systems becomes unstable. Unfortunately, as of today, this issue has not received enough attention in modern scientific literature. The article considers the issue of determining the roughness coefficient based on the materials of field experiments on irrigation systems of Ukraine for its further use in the Saint-Venant equations for unsteady water movement in open prismatic channels. The authors of the article conducted an analysis of the errors of field measurements of maximum depths, calculation area of live sections, etc. The absolute error of finding the drop in water levels in individual sections of the channel was determined. Among the issues that were covered in the publication under consideration, the main attention was paid to the issue of studying the effect roughness coefficient on flow elements during unsteady movement in melioration (irrigation) systems. The results of field measurements are also given, a detailed overview of field data is provided, and the parameters measured at different sections studied channel are listed. An indicative evaluation and analysis errors of the performed measurements was carried out, and recommendations were given for determining the average values of roughness coefficients for irrigation channels (channels) with a well-planned bottom and slopes, as well as for banks not covered with vegetation. The results processing of field observation data are summarized in a table, which presents a comparison calculated values of the roughness coefficients and a graph dependence of the roughness coefficients on the speed factor (Schezi coefficient)

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