Abstract
The aim of article is to develop the method of calculating the free-surface profile of undular jump for correct evaluation of its characteristics influence on tailrace channel erosion. The research method is based on using the differential equations of wavelike near-critical flows free-surface profile with taking into account the possible non-hydrostatics in their initial cross-section, energy losses and wave attenuation along the length. The different methods of calculating the free-surface profile of undular jump were analyzed. It was paid special attention to consider this phenomenon as combination of solitary wave and cnoidal waves. The article emphasized the results of undular jump experimental researches which were made by authors on different laboratory setups. The comparison of theoretical and experimental data showed their good convergence and confirmed the conceptual correctness of developed method. The scientific novelty is taking into account total important factors such as possible deviation from hydrostatics in the initial cross-section, energy losses and wave attenuation along the length. The practice value is determining the length of wave attenuation that is needed to accept the length of tailrace channel paving.
