Visualization of River Water Flow in Hydrodynamically Active Areas under Different Flow Regimes

• Main Authors: Volodymyr Snitynskyi, Petro Khirivskyi, Ihor Hnativ, Oleg Yakhno, Oleg Machuga, Roman Hnativ
• Format: Article
• Language: English
• Published: Polish Society of Ecological Engineering (PTIE) 2021-10-01
• Series: Journal of Ecological Engineering
• Subjects: surface waters; mountain rivers; flow visualization; self-cleaning processes; hydrodynamically active areas; cavitation phenomena
• Online Access: http://www.jeeng.net/Visualization-of-River-Water-Flow-in-Hydrodynamically-Active-Areas-under-Different,141385,0,2.html

It is established that in the territory of the Stryi river basin the natural landscapes are maximally preserved in comparison with other regions of Western Ukraine, but in modern conditions we observe an increase of negative anthropogenic impact on the quality of natural waters. Important for the efficiency of self-purification processes are hydrodynamic barriers or hydrodynamically active areas (HAA) of mountain rivers, where there is a significant oxygen saturation of the water flow, which activates the processes of biochemical and biological self-purification of surface waters. To verify the results of theoretical and field research, an existing experimental setup was designed and improved, which provided conditions for modeling the flow of mountain rivers in accordance with the laws of similarity theory and the principles of hydrodynamic modeling. Based on the results of field observations in the foothills of rivers, as well as regulatory and design documentation, the limits of the main operating factors were determined, namely the Freud number, flow depth and flow rate, which are decisive in studying the impact of HAA on flow self-cleaning processes. By changing the length of the tray section, the gullies and the waterfall niche of the real hydrodynamically active section were simulated, on which field experiments on the Tyshivnytsia River were conducted. In the studies, measurements were performed at different flow regimes, which simulated different hydrological parameters. To analyze the impact of HAA on self-cleaning processes, the flow was visualized using photography. The change of structure of a stream of natural waters at passage of HAA is established. The high oxygen saturation of the river waters of the Stryi river basin is caused by the influence of HAA, which contribute to the purification of polluted waters from biological pollutants and other man-made pollutants and form the high quality of water resources in the region. A method of modeling and visualization of mountain rivers in the laboratory has been developed.