RESEARCH OF THE UNSTEADY MOVEMENT OF LIQUID IN OPEN CHANNELS

Abstract

Summary. In this work, the transient processes were studied and quantitative calculations were performed on the example of irrigation canals located in the south of Ukraine. Field, laboratory, and mathematical studies of the hydraulic structures' throughput capacity were carried out. Transient processes that arise in the process of re-regulation of the water consumption regime or as a result of emergencies, which are important aspects of the functioning of irrigation canals, were investigated. The basis of such processes is the unsteady fluid motion. To study the peculiarities of unsteady motion in irrigation canals, the general characteristics of the filling wave were determined, the instantaneous profiles of the free surface of the flow and changes in water levels over time in fixed sections along the canal were analyzed, and theoretical calculations were compared with the results of field observations. Changes in the average velocity of the filling wave front propagation along the channel were also determined, and the conditions for the transformation of the maximum flow along the entire length of the channel were studied. The algorithm for solving the problem uses a previously developed model based on the numerical integration of the Saint-Venant equations. Numerical calculations of transient processes were performed using a program that made it possible to calculate optimal control options, evaluate the effectiveness of the chosen method of automated water supply regulation, and calculate typical operating modes of the canal. As an example, to solve the problem of water distribution management, various schemes of automatic regulation of water flows and levels on the North Crimean Canal were considered. The results of the calculations were experimentally verified in real conditions with the same initial data. The experiments were carried out at the facilities located on the Razdolnensky Canal. The results of field observations were modeled and tested in the hydraulic tray of the department's laboratory. The field and laboratory studies confirmed the results of preliminary calculations. Keywords: hydraulic structures, unsteady motion, maximum flow transformation, water resources, irrigation systems.