The research was carried out at the Department of Hydraulic Engineering, Faculty of Civil Engineering, Slovak University of Technology in Bratislava with close cooperation with Institute of Water Structures, Faculty of Civil Engineering, Brno University of Technology. One of the important goals was the determination of the most accurate approach related to the computational fluid dynamics modeling of the air-water interaction. Research consists of two main research methods to ensure the accuracy, set up the possibilities of cooperation and the results control. The first method was the physical model of broad-crested weir installed in collapsible canal in hydraulic laboratory and the second was numerical computational fluid dynamics model of broad-crested weir created in same scale. In free surface flows the air entrainment phenomena plays an important role. Air entrainment is affecting the volume fraction, velocity field, energy dissipation and many other parameters related to dynamic behavior of water near the crests. Different approaches were carried out to identify most accurate computational fluid dynamics setup compared to physical model measurements. Compared results and the accuracy assessment are summarized and the best computational fluid dynamics parameterization is recommended.
Authors:Martin Pavúček, Ján Rumann, and Peter Dušička
One of the main problems at the Hričov weir is the scour development in the riverbed just downstream. It is caused of construction the size of the stilling basin was significantly shortened. Flow energy is dissipating just partially. Each flood makes scour close to the foundations of the structure, which potentially endangers its stability. A permanent solution was experimentally investigated in the hydraulic laboratory at the 2D model in a scale of 1:40. Different variants of the secondary stilling basins were designed to minimize creating scours. The investigation and its results are described in this paper.
Authors:Lucia Bytčanková, Ján Rumann, and Peter Dušička
The structural parts of intake structures directly affect the flow velocity distribution in the turbine intake of small hydropower plants, where inhomogeneous flow leads to uneven load of the turbine units causing operational problems. A 2D numerical flow modeling was used for investigations of the flow in an intake structure of a low-head small hydropower plant. The effects of shape changes of the intake structure on the flow velocity distribution in the turbine intakes were investigated and assessed proving significant effect of the shapes of the intake structure on the flow homogeneity in turbine intakes.