Purpose: to determine the cause of wave motion formation in the discharge tunnel of the vacuum shaft energy absorber model of the Rogun Hydroelectric Power Plant spillway in Tajikistan.
Materials and methods. The studies were conducted in the Culvert Structures Laboratory of the Hydraulic Structures Department of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy on a hydraulic model of the Rogun Hydroelectric Power Plant spillway. The model is made at a scale of 1:100 and reproduces the main elements of the structure: the feeder channel, the gate chamber, the vertical energy absorber shaft, and the discharge tunnel. The experiments were conducted for two modes: with and without forced air supply to the shaft. In each series, the relative gate opening was varied in the range from 0.1 to 1.0. Water flow rates were measured volumetrically using a measuring tank and a stopwatch, and the vacuum was measured using piezometers connected to characteristic points of the shaft. Flow visualization was accomplished using photography.
Results. The causes of wave motion in the discharge tunnel were identified. A model shaft with a well located below the cross-section bottom at the tunnel inlet was studied, which partially resolved the problem of wave motion formation. Experimental studies also revealed that the nature of water motion in the discharge tunnel of a shaft spillway significantly depends on the operating mode of the absorber shaft and the presence or absence of air supply. To improve the flow-to-shaft interface, deflectors installed on the supporting faces of the gate chamber and the gates themselves were tested.
Conclusions. It was found that when the discharge tunnel-to-shaft interface is located at low elevations in close proximity to the shaft bottom, wave motion of water in the discharge tunnel occurs in the event of reduced flow rates. This is caused by a mismatch between the pressure required to pass the reduced water flow rates and the water depth in the shaft required to dampen the increasing flow energy.
doi: 10.31774/2712-9357-2026-16-1-250-262
shaft spillway, hydrodynamic pressure, energy absorber, vacuum, hydroelectric power station
Alekseev D. A., Khanov N. V., Zhukova T. Yu. Results of a study on the influence of a shaft energy absorber on the water wave motion formation in a discharge tunnel. Land Reclamation and Hydraulic Engineering. 2026;16(1):250–262. (In Russ.). https://doi.org/10.31774/2712-9357-2026-16-1-250-262.
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the study was carried out within the framework of the project for the creation and development of the engineering center of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy (agreement No. 075-15-2025-543 of June 16, 2025).
