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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Scour reduction around bridge pier using the airfoil-shaped collar

Gupta, L.K., Pandey, M., Raj, P.A., Pu, Jaan H. 12 October 2024 (has links)
Yes / Scouring around the bridge pier is a natural and complex phenomenon that results in bridge failure. Failure of bridges have potential devastation and public safety and economic loss, which lead to political consequences and environmental impacts. Therefore, it is essential to countermeasure the scour around the bridge pier. This paper studies the effects of four different airfoil-shaped collars (i.e., bc1 = 1.5b, bc2 = 2.0b, bc3 = 2.5b and bc4 = 3.0b, where bc and b are the diameter of the airfoil-shaped collar and pier, respectively) as a scour countermeasure. All the experiments are conducted under clear water conditions with uniform sediment and a constant water depth (y) of 10 cm. Airfoil-shaped collar is placed at four elevations, i.e., bed level, y/4, y/2 and 3y/4 above the sediment bed level. It is observed that the maximum percentages of scour reduction of 86, 100 and 100% occurred due to protection provided by the collar bc2, bc3 and bc4, respectively, at sediment bed level. So, collars bc2, bc3 and bc4 are efficient at the sediment bed level. The profiles of scour hole show that the length of the transverse scour hole is greater than that of the longitudinal one. Numerical investigation of the morphological changes in sediment bed and scour depth contours is developed using the FLOW-3D for the pier with and without the airfoil-shaped collar.
12

Stanovení pracovního rozsahu a účinnosti vodního trkače / Determination of the working range and efficiency of the water hammer pump

Růžička, Jakub January 2019 (has links)
This thesis focuses on setting the range and efficiency of a water ram pump through experimental measurements in a laboratory. The measurements were carried out on three different constructions of water ram pump, each of the designed and assembled by the author of this thesis himself, to find out whether the weight on the pulsating valve has an influence on the water ram pump efficiency. Further on this thesis aims at the comparison of up to now methods of water transport arrangement used at a summer camp and the usage of the water ram pump and its advantages. The principal of water ram pump originates in hydraulic impact that is being precisely described in a great detail as well. On of the chapters even includes the placement manual for the water ram pump and its overall assembly and connexion. Because the presence of floating debris is inevitable, this thesis also deals with the possibility to solve the incoming water impurities by adding an inflow gating to prevent such problem. This inflow gating has only been designed in a Flow 3D programme to introduce the idea and functions.
13

Analýza proudových poměrů v okolí nové vodní elektrárny / Hydraulic analysis in the surrounding of hydro power plant

Lorenc, Václav January 2018 (has links)
The diploma thesis deals with analysis of flow ratios at the hydraulic plant Klecany – Roztoky, located in the region of Střední Čechy at Vltava river (km 37,08). At this site 3D streaming of superficial water was simulated aiming to evaluate the influence of potencial construction of the new hydroelectric power plant Klecany II on existing Klecany I. Using all of the base documentation available, 3D models of current and planned conditions were created to serve as base for calculation in FLOW 3D. The first part of the thesis describes, how the planned construction of the new hydroelectric power plant Klecany II could influence the current fairway at the inlet 400 m3/s. The second part analyses shape of planned flow hydroelectric power plant Klecany II for flow Q90d, equal to 180 m3/s. All of the results are presented in intelligible charts and images.
14

Stanovení pracovního rozsahu a účinnosti vodního trkače / Determination of the working range and efficiency of the water hammer pump

Růžička, Jakub January 2019 (has links)
This thesis focuses on setting the range and efficiency of a water ram pump through experimental measurements in a laboratory. The measurements were carried out on three different constructions of water ram pump, each of the designed and assembled by the author of this thesis himself, to find out whether the weight on the pulsating valve has an influence on the water ram pump efficiency. Further on this thesis aims at the comparison of up to now methods of water transport arrangement used at a summer camp and the usage of the water ram pump and its advantages. The principal of water ram pump originates in hydraulic impact that is being precisely described in a great detail as well. On of the chapters even includes the placement manual for the water ram pump and its overall assembly and connexion. Because the presence of floating debris is inevitable, this thesis also deals with the possibility to solve the incoming water impurities by adding an inflow gating to prevent such problem. This inflow gating has only been designed in a Flow 3D programme to introduce the idea and functions.
15

Numerické modelování proudění v bezpečnostním přelivu / Numerical modeling of flow in spilway

Svoboda, Jiří Unknown Date (has links)
The goal of the diploma thesis is the numerical modelling of flow in planned spillway of the Boskovice dam. In the introduction of this diploma thesis are described and divided basic spillways according to their types and profiles. There are also mentioned emergency spillways. Then the thesis introduces the description of calculation of overflow quantity, the description of mathematic modelling and used turbulent models. The next part is concerned with the technical description of the Boskovice dam, the creation of virtual 3D model of spillway and spillway chute in the AutoCAD 2020 software and concerned with the control and revision of model in the Blender software. In the end of the thesis are mentioned results of numeric modelling of flow gained from the Flow-3D software and the comparison of results with the research of hydraulic model implemented at Water structures institute of Faculty of Civil Engineering of BUT.
16

A Cell Preparation Stage for Automatic Cell Injection

Lu, Cong 14 December 2011 (has links)
Cancer study and drug selection research attract more and more researchers, which need a significant laboratory technique, named cell injection. Hundreds of cells are loaded on devices and injected to investigate the behavior of the cells. Traditionally, cell injection is performed manually, which leads to human fatigue, is time-consuming and has a low success rate. Therefore, a system which can replicate the actions of what technicians do, such as to aspirate cells, transfer cells, immobilize cells, and release cells automatically, is needed. This system must be accurate, reliable, and efficient and operate without human intervention. A cell-transfer-cover and a cell-holder have been fabricated and a cell injection system has been set up to investigate the performance of the newly created device. Simulations and experiments have proven that this system would carry out the entire process of cell injection with the result of enhancing the speed of this important activity.
17

A Cell Preparation Stage for Automatic Cell Injection

Lu, Cong 14 December 2011 (has links)
Cancer study and drug selection research attract more and more researchers, which need a significant laboratory technique, named cell injection. Hundreds of cells are loaded on devices and injected to investigate the behavior of the cells. Traditionally, cell injection is performed manually, which leads to human fatigue, is time-consuming and has a low success rate. Therefore, a system which can replicate the actions of what technicians do, such as to aspirate cells, transfer cells, immobilize cells, and release cells automatically, is needed. This system must be accurate, reliable, and efficient and operate without human intervention. A cell-transfer-cover and a cell-holder have been fabricated and a cell injection system has been set up to investigate the performance of the newly created device. Simulations and experiments have proven that this system would carry out the entire process of cell injection with the result of enhancing the speed of this important activity.
18

Návrh profilu pro zachycení povodňového pláví na řece Bečvě / Design of the control profile to retain flood debris at the Bečva river

Lokajová, Hana January 2015 (has links)
The work deals with a theoretical description of mathematical model and practical aspects of model simulation. Subsequently, it solves the current flow and the two design versions of the flowing debris trap profile. For the original channel and for the two designed versions two simulations were done for the flows of Q2 and Q5. As part of the work the theoeretical calculation of velocity in two cross sections of the existing channel was realized for the existing channel, which were due to calibration of the model. Results were compared at the same cross sections in the existing channel simulation solutions. Simulations are created in FLOW-3D. The purpose of this thesis is to determine whether the construction of trap profile is feasible.
19

Numerical Simulation of Three-Dimensional Tsunami Generation by Subaerial Landslides

Kim, Gyeongbo 1978- 14 March 2013 (has links)
Tsunamis are one of the most catastrophic natural events impacting coastal regions often generated by undersea earthquakes. Nevertheless, in enclosed basins, i.e., fjords, reservoirs and lakes, subaerial or submarine landslides can initiate devastating tsunamis with similar consequences. Although a subaerial or submarine landslide that impinges into a large water body can generate a tsunami, subaerial landslides are much more efficient tsunami generators than its counterpart. In this study we aim to integrate laboratory scale experiments of tsunami generation by subaerial landslide with numerical models. The work focuses on the numerical validation of two three-dimensional Navier-Stokes (3D-NS) models, FLOW-3D and our developed model TSUNAMI3D. The models are validated based on previous large scale laboratory experiments performed by a tsunami research team lead by Dr. Hermann Fritz, Georgia Institute of Technology. Three large scale landslide scenarios were selected from the set of laboratory experiments, namely, fjord like, headland and far field coastline. These scenarios showed that complex wave fields can be generated by subaerial landslides. The correct definition and evolution of the wave field are key to accurate modeling the ensuing tsunami and its effect in coastal regions. In this study, comparisons are performed between numerical results and laboratory experiments. Methodology and key parameters for soil rheology are defined for model validations. Results of the models are expected to be under the allowable errors indicated by the National Tsunami Hazard Mitigation Program (NTHMP), National Oceanic and Atmospheric Administration (NOAA) guidelines for validation of tsunami numerical models. The ultimate goal of this research is to obtain better tsunami calculation tools for real-world application of 3-D models for landslide tsunamis, which are necessary for the construction of inundation maps in the Gulf of Mexico and the Caribbean regions.
20

Numerické modelování proudění v bezpečnostním přelivu vodního díla Letovice / Numerical Modelling of Flow over Spillway of the Letovice Dam

Křivohlávek, Roman January 2018 (has links)
This diploma thesis deals with numerical modeling of water flow. The numerical model was created to simulate the flow of water through the spillway of the Letovice dam. The spillway is constructed as a side channel and is located on the right bank. Autocad 2015 was used to create a 3D model, and FLOW-3D version 11.0.4 was used to create a numerical model.

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