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Energy harvesting from oscillating body in a fluid flow
Słowiaczek, Kamil ; Pluskal, Tomáš (referee) ; Habán, Vladimír (advisor)
In this thesis, numerical simulations of a flow around a cylinder with prescribed harmonic motion are conducted. To set the cylinder in motion, a dynamic mesh is utilized, and the movement is defined using a UDF (User-Defined Function). The influence of the amplitude of displacement and the frequency of motion on the device's performance is examined. Additionally, the additional effects of the fluid acting on the body are evaluated. Finally, an experiment designed to validate the simulations is described.
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Vortex induced vibrations
Szarka, Beáta ; Pluskal, Tomáš (referee) ; Rudolf, Pavel (advisor)
Tato bakalářská práce se zabývá kmitáním vyvolaném vírami na různých průřezech. Teoretická část poskytuje přehled současných trendů výroby energie a představuje typ hydrokinetického sběrače energie VIVACE konvertor. Hlavním principem systému je odtrhávání víru a vznik Kármánové vírové stezky podél tělesa ponořeného do proudící tekutiny. Praktická část se zabývá vyhodnocením různých profilů podle sil působící na těleso, frekvencí a Strouhalového čísla pomocí 2D CFD simulací. Výstupem je výběr ideálního tvaru průřezu válce pro konvertor VIVACE.
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Design study of energy harvestor based on vortex induced vibrations
Háze, Matyáš ; Habán, Vladimír (referee) ; Rudolf, Pavel (advisor)
The formation of vortices and periodically acting forces during the flow around bodies has been a long-standing issue addressed by engineers. Most of the focus has been on minimizing and suppressing these phenomena, which adversely affect engineering structures. However, it appears that it might be possible to amplify this phenomenon and purposefully use it for energy production. Several research projects have already been conducted on this issue, and another is currently underway in collaboration with other European universities at the Viktor Kaplan Department of Fluid Engineering. This bachelor's thesis aims to conduct a review of the ongoing projects and propose a new solution, which will be tested in the OFI laboratories and will be part of the ongoing measurements.
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Checking of heat exchanger to flow-induced vibration
Mazura, František ; Pernica, Marek (referee) ; Buzík, Jiří (advisor)
This bachelor thesis focuses on the thermal-hydraulic design of the heat exchanger and flow induced vibrations checking. The introductory part describes the basic distribution and function of heat exchangers. The next part introduces the thermal-hydraulic design in the Python programming language using the Kern‘s method for an U-tube heat exchanger. Thermal-hydraulic design outputs are compared with values from HTRI software. Subsequently, the issue of the flow induced vibrations is characterized and the checking of these vibrations according to the normalized TEMA standard is performed. Finally, the heat exchanger is checked using the Poddar & Polley graphical method.
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Eigenmodes of the swirling flow
Jízdný, Martin ; Pochylý, František (referee) ; Rudolf, Pavel (advisor)
This thesis deals with study of dynamics of the swirling flow. The swirling flow occurs frequently in hydraulic machinery (e.g., vortex rope in draft tube of the hydraulic turbine) and often influences operation of these machines. For this reason, sufficient knowledge regarding this characteristic flow is necessary for subsequent improvement of hydraulic machines. The theoretical part of this thesis contains description of flow instabilities and their manifestations, notably Kármán vortex street and vortex rope. In the next part, two methods are applied to these two transient flows in order to identify their specific dynamic properties. The first method, Fourier transform, enables to find frequencies of transient flow. The second method, proper orthogonal decomposition (POD), enables to identify planar or spatial eigenmodes of a specific swirling flow. Proper orthogonal decomposition is used in this thesis to identify planar eigenmodes of Kármán vortex street and spatial eigenmodes of vortex rope.
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Solution of flow and formation of vortex structures behind a free-standing pillar
Pluskal, Tomáš ; Pochylý, František (referee) ; Fialová, Simona (advisor)
The instability of the flow and the formation of vortices when surrounding free-standing pillars is a problem that has been solved for a long time. In most engineering applications we try to minimize their influence. However, some newer applications require them to be maximized. This deals with the study of these effects on the public street lamp using computer modelling in the Ansys Fluent and their use for the production of electricity. The information obtained in this way is then used for the design of a vibration generator, which is then used to transform the energy from mechanical vibrations to electricity.
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Proudění tekutiny v okolí překážky kruhového průřezu
BELOV, Sofya
This bachelor thesis deals with the issue of fluid flow around an obstacle of a circular cross-section, including the phenomenon called Kármán vortex street. Numerical code Lare2d is used for numerical simulations of fluid flow at various Reynolds numbers and extending the issue to magnetic field environment.
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Checking of heat exchanger to flow-induced vibration
Mazura, František ; Pernica, Marek (referee) ; Buzík, Jiří (advisor)
This bachelor thesis focuses on the thermal-hydraulic design of the heat exchanger and flow induced vibrations checking. The introductory part describes the basic distribution and function of heat exchangers. The next part introduces the thermal-hydraulic design in the Python programming language using the Kern‘s method for an U-tube heat exchanger. Thermal-hydraulic design outputs are compared with values from HTRI software. Subsequently, the issue of the flow induced vibrations is characterized and the checking of these vibrations according to the normalized TEMA standard is performed. Finally, the heat exchanger is checked using the Poddar & Polley graphical method.
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Eigenmodes of the swirling flow
Jízdný, Martin ; Pochylý, František (referee) ; Rudolf, Pavel (advisor)
This thesis deals with study of dynamics of the swirling flow. The swirling flow occurs frequently in hydraulic machinery (e.g., vortex rope in draft tube of the hydraulic turbine) and often influences operation of these machines. For this reason, sufficient knowledge regarding this characteristic flow is necessary for subsequent improvement of hydraulic machines. The theoretical part of this thesis contains description of flow instabilities and their manifestations, notably Kármán vortex street and vortex rope. In the next part, two methods are applied to these two transient flows in order to identify their specific dynamic properties. The first method, Fourier transform, enables to find frequencies of transient flow. The second method, proper orthogonal decomposition (POD), enables to identify planar or spatial eigenmodes of a specific swirling flow. Proper orthogonal decomposition is used in this thesis to identify planar eigenmodes of Kármán vortex street and spatial eigenmodes of vortex rope.
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