The aim of this study was an investigation of tile drain flow velocity under variable hydraulic conditions and of tile drain discharge using an ultrasonic flow meter. There is an essential variance between velocity values measured by an ultrasonic flow meter and reference values determined by a laboratory method. Differences result from specific measurement conditions, which appear in drainage pipe systems. The values of velocity measured by ultrasonic flow meters were higher than the reference values for three examined flow phases: Free, transient, and pressured flow. The discharge from a tile drain working on a partially filled up pipe in no-pressure conditions should be calculated by an adapted equation based on the California pipe method, whereas the discharge from a completely filled up drain pipe working over pressure should be calculated as a ratio between 0.428 times the measured velocity and the pipe cross-section area.
Sediment segregation on weirs of lowland rivers Erosion and accumulation processes in the vicinity of water structures develop depending on the life of the facility, hydrological regime and morphology of the riverbed. Diversification of flow characteristics affects the segregation of bed sediment on section of period of weirs. Knowledge of factors determining granulometric diversity of bottom material allows for more appropriate bed and riverbanks protections design. It also enables estimation of the conditions of sediment transport down the watercourse and its participation in the balance of the transport of bottom material in the watercourse. Areas where sediment accumulates on the water structures are up water and down water positions, stilling basin and other cavities of the structure. The article presents an analysis of granulometric composition of bottom material in selected lowland weirs. Research facilities are weirs located on lowland rivers. Segregation of sediment material was observed on weir sections. Thickest sediment is piled in up water, smallest in down water.
Zarys treści: W artykule przedstawiono sposób konstruowania diagramu potrójnego, jak również zasady wydzielenia na jego obszarze pól orientacji, ułożenia oraz kształtu ziaren według przestrzennego układu współrzędnych. Zorientowanie układu XYZ względem boków gabionu i głównego kierunku przepływu wykorzystywane jest w ocenie przepustowości przepuszczalnej części progów gabionowych. Potrójny diagram klasyfikacyjny zawiera trzy elementy identyfikacyjne i umożliwia wprowadzenie wymiarów ziarna, jego kształtu oraz ułożenia względem układu współrzędnych: pola trójkątnego układu współrzędnych, którego boki wyznaczają osie XYZ, pola orientacji ziarna w przestrzeni identyfikowanego wymiarami A, B, C, pola kategorii kształtu ziaren wyznaczone według bezwymiarowych stosunków B/A i C/B.
The study aimed to adapt selected formulas for the estimation of the maximum depth of local scour in the area of the bridge pillar model: Begam formula, Laursen and Toch equation and the equation included in the Regulation of the Polish Minister of Transport and Marine Economy of 30 May 2000 on technical requirements for road engineering structures and location of these structures. The results of own laboratory tests were used for the adaptation. A total of 19 series of measurements with different durations, water flow rates and water depths were performed. The tests were carried out on a model of a washable flume model with a sandy bed, with a single cylindrical bridge pier. The formulas were optimized using the Monte Carlo sampling method. The best match among the original formulas was obtained for Laursen and Toch’s formula (mean relative error 15.3%). For Begam’s formula, an average relative error of 21.6% was received, and for calculations using the Regulation equation, a relative error of 30.1% was obtained. Optimization of formulas using the Monte Carlo sampling method resulted in a formula that describes laboratory data with a mean relative error of 8.8% based on the Begam equation, a mean relative error of 13.8% based on the Laursen–Toch equation, and 28.5% for the formula based on equation included in the Regulation.
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