Poplavskyi D. Improvement of the methods for calculating the cnoidal waves parameters with taking into account the non-hydrostatics in the initial section and wave diminishing along the length

Thesis shows improvement of methods for calculating the parameters of the cnoidal waves. In the dissertation work, the theoretical and experimental researches of geometrical, kinematical and dynamical characteristics of cnoidal waves were carried out. It was detailed described the methods of hydraulic simulation of cnoidal waves in laboratory conditions and analyzed the results of experiments. Based on it, the dependencies and methods for determining parameters and calculating the free-surface profile of cnoidal waves were scientifically substantiated. As a result of theoretical and experimental studies, the method of calculating the parameters and free-surface profile of cnoidal waves with taking into account the non-hydrostatics in the initial section and wave diminishing along the length, was improved. Using the results of field studies, recommendations for calculating the main parameters and free-surface curve of the cnoidal waves in tail race channel of the Migiya hydropower plant were developed. The developed recommendations for the method of calculating the profile of the free-surface of cnoidal waves with taking into account the non-hydrostatics in the initial section and wave diminishing along the length, allows to determine the maximum and second conjugated depths and wavelengths of the cnoidal waves. From a practical point of view, this allows more accurate determine the required margin for the level of the dam and dikes and length of the channel bank protection. Mentioned positions and conclusions in the dissertation can be used in the design, construction, operation and reconstruction of hydraulic structures, within which a phenomenon of undular jump can be formed, which will increase their reliability.