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Some aspects of modeling bed processes in trained rivers

Saulius Vaikasas ; Mindaugas Stankevičius

Journal of Environmental Engineering and Landscape Management, 01 March 2004, Vol.12(1) [Periódico revisado por pares]

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  • Título:
    Some aspects of modeling bed processes in trained rivers
  • Autor: Saulius Vaikasas ; Mindaugas Stankevičius
  • Assuntos: Bed Processes ; Turbulent Flow ; Hydraulic Modeling, Scales ; Engineering
  • É parte de: Journal of Environmental Engineering and Landscape Management, 01 March 2004, Vol.12(1)
  • Descrição: Physical modeling of sediment transport and morphology in rivers as well as wastewater dilution processes are closely related to the modeling of macro turbulent fluctuations. The physical modeling of hydraulic macro turbulent fluctuations is complicated and underestimated. The study of turbulent flow structure and verification as well as model calibration is required in this case. Some methods of model verification by means of kinematics and turbulent coefficients scaling α Ka , α x and α k are presented in the paper. Experience in hydraulic modeling of bed processes in the Neris and Nemunas rivers contributed to the viable results. As laboratory tests showed, after the scales of the Nemunas bed had been distorted 12 times, the turbulence of modeled flow increased causing 3 times more intensive wastewater dilution processes in a physical model of the Nemunas bed. When modeling the bed processes of the Neris in Vilnius in a hydraulic model with the scale distorted 6,7 times, it was determined that a more intensive turbulence caused a 25 % thinner bed soil layer and nearly 3 times higher velocity of vertical turbulent flow. This was considered when calculating the results obtained in a model into natural ones and when choosing proper means for designing riverbed hydraulic structures. Vaginiu procesu reguliuojamose upes dalyse bei dugniniu nešmenu judejimo modeliavimas labai siejasi su prototipo turbulentiniu fliuktuaciju modeliavimu. Tai būdinga ir šiuo būdu tiriant kanalizuoto vandens išleidimo, sklaidos bei susimaišymo procesus reguliuojamose upese. Turbulentiniu tekmiu fliuktuaciju modeliavimas sudetingas ir iki šiol mažai tyrinetas. Straipsnyje, atsižvelgiant i turbulentiniu fliuktuaciju bei kinematiškumo mastelius α Ka ; α x ir α k , pateikiama keletas atliekant hidraulini modeliavima gautu tekmes charakteristiku perskaičiavimo būdu. Akcentuojama, kad norint perskaičiuoti taip gautus rezultatus i natūrinius, būtina daugiau demesio skirti turbulentines tekmes struktūrai ir taikomu fiziniu modeliu veri‐ fikavimui bei kalibravimui. Aprašyti ir konkretus šiu perskaičiavimu pritaikymo pavyzdžiai tiriant Neries ir Nemuno reguliuojamu ruožu kinematika. Laboratoriniai matavimai parode, kad 12 kartu iškreipus Nemuno vagos mastelius, padideja modeliuojamos tekmes turbulentiškumas, kartu 3 kartus suintensyveja išleidžiamu i upe teršalu sklaidos bei susimaišymo procesai Nemuno vagos fiziniame modelyje. Modeliuojant vaginius procesus Neryje Vilniaus mieste, 6,7 karto iškreipto mastelio hidrauliniame upes modelyje gauta, kad del padidejusio turbulentiškumo 25 % sumažeja lyginamasis priedugnio sluoksnio storis ir beveik 3 kartus padideja turbulentinis vertikalusis sūkuriu kilimo greitis. I tai atsižvelgta perskaičiuojant modelyje gautus duomenis i natūrinius ir parenkant upiu vagu reguliavimo būdus bei priemones.
  • Idioma: Inglês

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