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The solution of dynamic response of hydraulic steel structures interacting with fluid
Feilhauer, Michal ; Králík,, Juraj (referee) ; prof. Ing. Alois Materna, CSc., MBA (referee) ; Salajka, Vlastislav (advisor)
Behaviour prediction of hydraulic steel structures with the view to surrounding influences in various design dispositions is a fundamental condition for operational reliability assessment of the analyzed construction. Reliable characteristics of construction behaviour defined by the specification of its movement within changes caused by time and environmental influences is of great importance. In currently used engineering mechanics formulation it concerns setting the response of the defined construction or its part to the given time variable mechanic load. Required response values, which are necessary for evaluation terminal dispositions of capacity and usability of the construction, are trans-location and tension, or values thence derived. Calculation is basic means for response prediction of construction. The thesis presented deals with complex multi-physical behaviour problems of water supply constructions in fluid structure interaction. There are presented various approaches to calculations of static and dynamic qualities of constructions. These approaches are divided into so called “direct method”, which is based on direct connection between two physical fields and the calculation is performed by the method of final elements, and so called “indirect method” , which is based on connection of two physical fields by means of various interfaces, which are described in this thesis. In case of indirect method, the calculation of running liquid is performed by the method of final volumes and the construction calculation is performed by the method of final elements. Within the scope of this thesis, static and dynamic responses of water supply constructions have been solved with the use of the above mentioned approaches. The results of the calculations in the scope of this thesis have been compared with the findings of performed experiments. The final part of the thesis describes the results and generalized findings gathered from the tasks by various approaches.
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Dynamic behavior od rotor dynamics system vibrating in a liquid
Kučera, Martin ; Pohanka, Lukáš (referee) ; Malenovský, Eduard (advisor)
This thesis deals with dynamic behavior of rotor dynamics system vibrating in a liquid. Work is factually oriented on influence of the liquid to natural frequences of rotor of vortex turbine. There is described the creation of geometric and computational model of the system and the results of natural frequences and damping in dependence on environment are presen-ted. There are compared variations in natural frequences of the rotor system, which are caused of the interaction of the various level of the water environment. The step of integration are tested and compared for choise solving method. Problem is solved by computational simulation in commercial software ANSYS 11.0 There is used software tools Multiphysics/FSI.
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Spectral properties of basilar membrane in the cochlea of the inner ear
Jozíf, Lukáš ; Dušek, Daniel (referee) ; Mišun, Vojtěch (advisor)
This thesis aims to verify the function of the cochlea as a spectrum analyzer based on computational modeling of macro-mechanics of the cochlea using FEM. I aim to identify the spectrum of the basilar membrane, which is dependent on the variability of geometry, material characteristics and the presence of liquid environments. Interactions between liquid and solid phases is described by fluid-structure interaction in the system ANSYS. The model is linear and does not pursue an active policy of metabolic processes. Further the work focuses on the decomposition of the sound and check of two best known hypotheses about the transmission frequency of the sound to the brain.
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Stress-strength analysis of an impeller shaft using fluid-structure interaction modelling
Zifčáková, Barbora ; Vondál, Jiří (referee) ; Juřena, Tomáš (advisor)
This master’s thesis deals with numerical simulations of type FSI (Fluid Structure Interaction). Software used is ANSYS Fluent and ANSYS Mechanical. The aim of this thesis is to study the interaction between fluid flow in the mixing tank used in pharmaceutical industry to process eggshells and the agitator whose shaft has deformed during operation. CFD part consists of both one-phase and multi-phase transient simulations. The impact of solid body deformation on fluid flow is neglected hence only one-way Fluid Structure Interaction is considered for the simulations. Fluid flow in the tank and stress-strain behavior of the shaft is evaluated both in quasi-steady state and during start-up of the device. Computations showed that the impact of eggshells on agitator is negligible during operation (in quasi-steady state) unlike the behavior during start-up of the device when stresses and strains of the shaft are significantly higher. Possible reasons why the shaft deformed are presented and further numerical simulations are discussed and suggested.
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Analysis of pulse wave propagation in aorta
Tichoň, Dušan ; Klas, Roman (referee) ; Burša, Jiří (advisor)
The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
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Analysis of pulse wave propagation in aorta
Holubář, Oldřich ; Janíček, Přemysl (referee) ; Burša, Jiří (advisor)
This master thesis is focused on usage of monitoring pulse wave propagation in aortic system in a field of diagnostic abdominal aortic aneurysm (AAA). There is a description of cardio-vascular system and its pathology in a form of AAA. A summarization of temporary diagnostic method was created and some new methods were proposed. This new methods presume monitoring of pulse wave propagation. Fluid structure interaction (FSI) analyses of pulse wave propagation were performed on simplified models of geometry which representing specific sections of aorta. The goal of these analyses was to prove usage of FSI method in a future development of proposed diagnostic methods.
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Spectral/hp elements in fluid structure interaction.
Pech, Jan
This work presents simulations of incompressible fluid flow interacting with a moving rigid body. A numerical algorithm for incompressible Navier-Stokes equations in a general coordinate system is applied to two types of body motion, prescribed and flow-induced. Discretization in spatial coordinates is based on the spectral/hp element method. Specific techniques of stabilisation, mesh design and approximation quality estimates are described and compared. Presented data show performance of the solver for various geometries in 2D from slowly moving cylinder to high speed flow around aerodynamic profiles.
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Stress-strength analysis of an impeller shaft using fluid-structure interaction modelling
Zifčáková, Barbora ; Vondál, Jiří (referee) ; Juřena, Tomáš (advisor)
This master’s thesis deals with numerical simulations of type FSI (Fluid Structure Interaction). Software used is ANSYS Fluent and ANSYS Mechanical. The aim of this thesis is to study the interaction between fluid flow in the mixing tank used in pharmaceutical industry to process eggshells and the agitator whose shaft has deformed during operation. CFD part consists of both one-phase and multi-phase transient simulations. The impact of solid body deformation on fluid flow is neglected hence only one-way Fluid Structure Interaction is considered for the simulations. Fluid flow in the tank and stress-strain behavior of the shaft is evaluated both in quasi-steady state and during start-up of the device. Computations showed that the impact of eggshells on agitator is negligible during operation (in quasi-steady state) unlike the behavior during start-up of the device when stresses and strains of the shaft are significantly higher. Possible reasons why the shaft deformed are presented and further numerical simulations are discussed and suggested.
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Analysis of pulse wave propagation in aorta
Tichoň, Dušan ; Klas, Roman (referee) ; Burša, Jiří (advisor)
The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
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