Parameters of flow in a section compressed by transverse floodplain dams

Bakiev, Masharif; Kaxxarov, Uktam; Jakhonov, Azizjon; Panjiev, Sh

doi:10.1088/1757-899x/883/1/012016

Cited by 3 publications

References 3 publications

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Results of full-scale and laboratory studies of the spillway of HPP No. 2

2021

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In the article, based on the results of field measurements and calculations, recommendations are given for determining the roughness coefficient of the channel of the spillway. Based on the analysis of the literature and field research data, it was recommended to take the roughness coefficient of the channel of the spillway (canal) equal to n = 0.02 - for areas with steep slopes and without sediment deposits, and in areas with the worst condition of concrete surfaces and sediment deposits, take n = 0.0225. According to the results of field surveys of the canal, it was found that the hydraulic regime at the turning section No. 2 in the plan is characterized by an uneven distribution of depths in its cross-sections. This is due to the curvilinearity of the turning section of the channel, which has an unacceptably small radius of curvature in the plan causing centrifugal forces and rising levels along the concave wall, which led to an overflow of water over the top of the channel walls. As a result of the conducted experimental - laboratory studies of the turning section of the outflow tract (channel), recommendations are given for reducing the water incursion on the banks, the height of the walls.

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Results of full-scale and laboratory studies of the spillway of HPP No. 2

2021

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Flow spreading behind a combined dam with a through part of tetrahedrons on foothill rivers

2021

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The areas of the foothill rivers are distinguished by large bottom slopes reaching 0.004, with increased kinetics of the flow of more than 0.15, and by gravel-pebble sediments of the river bed and flow. An analysis of the studies performed on the regulatory structures showed that the bulk of them was performed for the conditions of lowland rivers. In the article, a design of a combined dam with a through part of tetrahedrons is proposed. The experiments were conducted in a flume with a rigid bottom and with a variable slope of. The modeling was performed according to Froude in a self-similar area. Experimental studies revealed the presence of two flow spreading modes depending on the bottom slope: a “calm” mode at iД < iκр and a “critical” mode at iД > iκр These modes are mainly influenced by the degree of constraint and the Froude number. In the previous articles, a solution to the problem was provided for the case iД < iκр, which covers the foothill sections of rivers at a “calm” mode. At a further increase in the degree of flow constraint n > 0.3 and the Froude number Fr > 0.15, a “critical mode” is observed. Here, a solution to the problem for this case is given. The problem, in this case, differs from the previously considered one by non-uniform distribution of velocities in the weakly disturbed core, a significant reduction in the length of the vortex zone; the vertical compression of the flow continues to the end of the vortex zone. The versatility of the velocity distribution in the zones of weakly disturbed core and intense turbulent mixing is experimentally substantiated. With theoretical studies, using the basic equations of applied mechanics, a method for calculating the velocity field was developed, and the planned dimensions of the vortex zones were established. The comparison with experimental data showed satisfactory agreement.

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