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Discharge coefficient of slit weirs
Havran, David ; Žoužela, Michal (referee) ; Zachoval, Zbyněk (advisor)
This work deals with experimental research, with outcomes of design and recommendation for determination of the discharge coefficient of the slit weir. At the same time states the possible effects on capacity. Then comparing the data with already existing ones. The thesis provides an overview and insight into the meaning of slit weirs as well. The goal is to recommend the determination of the discharge coefficient.
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Design of outlet and intake objects of Nové Heřminovy dam
Neuvirt, Petr ; Švancara, Jiří (referee) ; Zachoval, Zbyněk (advisor)
In this thesis was presented Nové Heřminovy dam with basic parameters. Requirements on bottom outlets and intake objects are presented as well. Analysis of used valves on all dams in Czech Republic was done as an underlay for suggestions of bottom outlets in this thesis. The main task was to suggest three variations of bottom outlets. Differences are in number of outlets, dimensions, placing and valves. Then variation of intake objects. Each of variation was verbally described and filled with calculations.
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Dewatering of foundation pit - numerical analysis
Krejzar, Vojtěch ; Boštík, Jiří (referee) ; Miča, Lumír (advisor)
The subject of the presented thesis is a foundation pit dewatering numerical analysis. The study is introduced with practical examples and the summary of the necessary theory. Individual subtasks are modeled as two or three-dimensional problem on a chosen foundation pit example. A comparison with analytical methods and theoretical knowledge about the problem is made. The studies focus on specifying the pumped water quantity, the shape of the depression curve, determining the size of the numerical model and the influence of the finite element network density. The steady-state flow cases, water table aquifer, a well system, sheet pile wall cutoff effect, surface drained pit and partial penetration cases are analyzed. The work proposes a method of modeling a well by FEM. The main output is a 3D analysis of a submerged excavation dewatered with a partially penetrated well system.
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Comparison of lightning detection networks over Czechia
Pacovská, Lucie ; Popová, Jana (advisor) ; Müller, Miloslav (referee)
This thesis focuses on ground-based lightning detection which is important since lightning discharges still cause casualties yearly worldwide. The thesis provides description of several ground-based lightning detection networks and an analysis of lightning data of three lightning detection networks covering the Czech Republic during 2015 - 2021. Specifically, the data of the World Wide Lightning Location Network (WWLLN), the amateur network Blitzortung and the European network EUropean Cooperation for LIghtning Detection (EUCLID) are investigated. The thesis examines the spatial and temporal characteristics of lightning discharges from the three detection networks, the relationship between lightning discharges and land cover from CORINE Land Cover data, and the relationship of lightning discharges with types of weather situations based on the Czech Hydrometeorological Institute (CHMI) data. The results show that there is not much difference in the temporal and spatial characteristics of lightning discharges among the three detection networks. The relationship between lightning activity and land cover is the same for the three networks. Unlike the relationship between lightning activity and land cover, the relationship between lightning activity and weather types is in good agreement among the...
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Analysis and use of wire cutting technology
Patočka, Josef ; Osička, Karel (referee) ; Kalivoda, Milan (advisor)
The diploma thesis focuses on the topic of electroerosive machining with greater emphasis on wire cutting technique. The first part clearly describes the principle of electroerosive discharge and its subsequent effects that cause material removal in the given working conditions. This includes the individual methods of electroerosion and the individual accessories that aid the process. The second part is a theoretical analysis of the cutting process using a wire electrode. It describes the machining method, machining strategy and a complete overview of the accessories that accompany the cutting process. The third part of the thesis includes a practical demonstration of the production of a typical representative for wire cutting and then there is evaluation from an economic point of view. Furthermore, there is clear analysis of the surface quality and the final evaluation of the condition of the component.
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Study of plasma discharge effect on distilled water pH
KOBRLE, Lukáš
This tesis is concerned with the influence of Gliding arc plasma discharge on the pH of distilled water while using different treatment time and distance between Gliding arc and the surface of distilled water. The theoretical part consists of research into various studies, whose main focus is the practical usage of Gliding arc and the possibilities of its use. The practical part contains the values of the measured quantities, models and graphs illustrating the effects of the process. The conclusion offers a brief summary of the findings and claims, whose correctness needs to be verified in further studies.
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Changes of selected surface water geochemistry parameters in relation to rainfall-runoff regime
Bartůšek, Adam ; Matoušková, Milada (advisor) ; Havlíková, Petra (referee)
This work deals with the study of changes in the geochemistry of surface waters in relation to the rainfall-runoff regime and its transformation. As rainfall-runoff extremes such as long episodes of drought with low flows or, conversely, high flows caused by extreme rainfall events have been increasing in recent years, it is important to understand how these phenomena affect water quality. Therefore, the main objectives of this work are firstly a literature search on the changes in surface water geochemistry during change of climate and precipitation-runoff regime and methods that can be used to quantify these changes, and then the application of some of these methods to the analysis of selected parameters and their changes in the Klíčava catchment. In addition to some climatic characteristics and flow rates, the analysis included basic parameters of geochemistry (flow rate, water temperature), physicochemical parameters (electrolytic conductivity, pH), some nutrients (forms of nitrogen and phosporus) and indicators of organic pollution and stream cleanliness (BOD5, CODCr, TOC and dissolved oxygen). In addition, the status and evolution of concentrations of some herbicide metabolites were briefly assessed. For data analysis, e.g. box plots, Mann-Kendall test, correlation coefficients or linear...
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Effect of climate change on hydrological extremes in montane catchments
Čermák, Daniel ; Langhammer, Jakub (advisor) ; Jeníček, Michal (referee)
This master thesis deals with the issue of low-flows in mountain catchments in the context of expected climate change. The Zdobnice, Vydra and Mumlava river basins are selected for analysis. In the first part of thesis, the meteorological and hydrological historical data are evaluated. This data are obtained from CHMI (Czech Hydrometeorological Institute). The work also focuses on estimating the possible change in flow rates in the distant future (2100). For these purposes, the conceptual model HBV is used. This model is often used for these types of analyzes due to its robustness. To evaluate the change, twelve alternative scenarios were created. These scenarious were based on the results of global and regional climate models related to each selected river basins. The model was calibrated using the automatic GAP optimization function. Based on the best results, the calibration period is set for the years 1980 - 1998. Climate models suggest increase of temperature in far future by 1.5 ř C - 4.5 ř C. At the same time, according to climate models, we can approximate a total precipitation change by 10 %. Based on climate changes, a shift in the runoff seasonality in the all river basins is evident. Seasonality change is most visible in the Zdobnice river basin. In terms of hydrological drought, an...
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Approaches to estimate wetland evapotranspiration and the evapotranspiration loss of groundwater from wetlands in the Liběchovka and Pšovka catchments
Pátek, Karel ; Bruthans, Jiří (advisor) ; Slavík, Martin (referee)
This work is dedicated to the study of evapotranspiration in wetlands. The theoretical part is an overview of methods that are used for estimation of evapotranspiration, especially in the wetland environment. The practical part is focused on measurement of evapotranspiration in the wetlands located in the upper part of the Pšovka and Liběchovka river watersheds. Periodical fluctuations of water table and water flow in the stream were observed there due to evapotranspiration. The role of evapotranspiration was dependent on the mean daily temperature and sunshine duration. For the warm sunny days the fluctuations indicated that in the studied wetland the maximal daily evapotranspiration can cause 32 % decrease of water flow in the stream. The evapotranspiration derived from stream flow oscilation reached 86 % of potential evapotranspiration based on Oudin method. Potential evapotranspiration in the Liběchovka wetlands in summer is capable to decrease the discharge of Liběchovka in similar way as groundwater abstraction.
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