Kinematic parameters of flow constrained by combined dams with through part of tetrahedra in compression region

Abstract

Every major river in the world consists of mountainous, foothills, and flat areas characterized by different flow regimes. The foothill areas differ in slopes i = 0.001 ÷ 0.004, flow kinetics Fr > 0.15, and the size of sediments. The riverbed is unstable, and the banks are prone to erosion. The construction of coastal protection structures requires solving complex issues related to their design. The analysis showed that most of the studies, including ours, were carried out for the conditions of lowland rivers. This work aims to establish the flow features of the foothill sections of a combined dam with a through part of tetrahedra when the ratio of the through part ℓs to the total length of the dam ℓd is greater than or equal to 0.5, i.e., ℓs/ℓd. ≥ 0.5 The presence of a satellite flow behind the through part, a weakly perturbed core, and the presence of two zones of intense turbulent mixing was experimentally established, and the universality of the velocity distribution, which obeys the theoretical dependence of Schlichting-Abramovich, was confirmed. It is once again confirmed that the dependence is on the slope of the bottom, the Froude number, the degree of constraint, and the formation of "calm" and "critical" flow modes. The nature of the level changes along the length of the compression region in the core, and the satellite flow differ from each other, and the alignments occur in the vertical compression alignment. The problem is implemented for the "calm" mode using an integral relation characterizing the law of conservation of momentum in the flow, the equation of conservation of flow, and the differential equation of uneven motion recorded for the satellite flow behind the through part of the combined dam. The presence of a satellite flow, two zones of intense turbulent mixing, and the different nature of the leveled regime of the main and satellite flows are taken into account. A comparison of theoretical solutions with experimental ones shows their similarity.