This (article) work is devoted to one, relatively unbalanced issue of the dynamics of hydraulic structures - the determination of hydrodynamic loads on the slabs of a high-pressure spillway in a cavitating flow in the presence of erosion-free energy absorbers. Working on the implementation of these studies, the authors simultaneously studied in laboratory pulsation loads on a real structure - elements of the downstream spillway devices, below – the Kafirnigan hydroelectric complex.
An improved hydraulic method for increasing the efficiency of operation of a damless water intake is presented. Physical picture of the movement of bottom and surface sediments during flow division in the damless water intake ABMCh (Amu-Bukhara machine channel). Analysis of the distribution of sediment along the channel of the channel showed that clay particles of suspended sediment <0.005 mm increase from the inlet to the main structure of the ABMCh from 15% to 36%. Dusty particles of suspended sediment d = 0.05 also increase from inlet to G.P. ABMCh from 38% to 66%. Sandy sediment particles d = 0.05 to 0.25 mm, on the contrary, decrease from 3% to 71%, and sediment particles d> 0.25 mm decrease from 1.30 to 0.15%. It is substantiated that the angle of the flow outlet to a greater extent influenced the formation of vortex zones at the entrance to the outlet. The size and intensity of the vortices at the inlet, in turn, determined the pressure loss, as well as the amount of sediment deposited at the water inlet, by the amount of sludge entering the outlet. The analysis of the experiments showed that the optimal threshold angle to the shore is (β = 30°, 45° 60°.; It is recommended that when setting the water intake mode it is necessary to take into account the fact that the reduction of the discharge angle to reduce the pressure loss at the inlet to the water intake, the latter is more intense carried by precipitating suspensions. It has been established that intense deformations of the Amudarya river channel occur in the area of the ABMCH water intake: Due to dredging of the channel by the dredgers, the pulp is thrown into the river channel, it turns out, as it were, storage of sediment on the right bank. This, in turn, leads to a narrowing of the river channel and siltation of the supply channel, which contributes to the movement of the channel to the left bank and complicates the intake from the river into the channel. Taking into account the complexity of the processes occurring during the division of the flow, it is necessary to consider the qualitative and quantitative aspects of this phenomenon ‘in pure form‘, without affecting the moving flow of various anti-ballistic devices. To improve the conditions of water intake and the quality of the incoming stream, an improved scheme with new structural elements is proposed.
The article considers a numerical study of the movement of water flow in the Amu-Bukhara Machine Channel (ABMCh-Bukhara region). Water intake to the inlet channel is carried out from one of the most muddy rivers in Central Asia in a damless manner, therefore, ensuring the flow of clarified water into the anterior chambers of pumping stations is an urgent task. A numerical study is a study of the hydrodynamic parameters of the flow and, based on the data obtained, the developed recommendation is the aim of this work. The determination of the main hydraulic parameters of the flow moving in the riverbed by numerical research is accepted as a research method. According to the developed model, consisting of hydrodynamic equations, based on the law of conservation of momentum and mass, data on the dynamics of velocities of the ABMCh supply channel are obtained and zones of uneven flow in the channel are determined. A recommendation has been developed that allows quasi-uniform movement, which helps to prevent the formation of deformation of the supply channel of the pumping station and the entry of suspended and bottom sediments into the chamber of the pumping station.
The article discusses the results of numerical studies of the flow movement with a sharp change in the parameters of the channel. Basically, the results of the study using the system of two-dimensional equations of hydrodynamics-Saint-Venant are analyzed. The divergent form of two-dimensional equations describing the movement of a water stream at a site of regulation of a channel by protective and regulatory dams is given. The influence of the length step on the results of numerical experiments is investigated numerically. Graphs of the time variation of the longitudinal velocity component behind the sudden double expansion of the channel are compiled. The flow was unsteady all the time and had the character of stationary pulsations, and the finer the grid, the richer the spectrum of these pulsations. It was noted that in numerical calculations, the time step in the calculations was always much less than the minimum pulsation period, therefore, these pulsations were not associated with difference oscillations that can arise when approximating by central differences. It is concluded that, according to the authors from the following and the present work, they collectively show that the pulsations on different grids differ significantly, the average values of the velocities are close, and thereby the solution for the average values is well converged, this shows that the pulsations are a property source equations of Saint-Venant. The applicability of the numerical model, consisting of two-dimensional shallow water equations, the vector equation of momentum conservation and the scalar equation of mass conservation, in description the flow with the presence of circulation zones, which is typical when water flows are constrained by protective-regulatory structures. In this case, the solution pulsates around a certain average value, and the average length of the circulation zone behind the sudden expansion of the open flow is in good agreement with the laboratory experiments of G.L. Mazhbits.
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