National Repository of Grey Literature 18 records found  previous11 - 18  jump to record: Search took 0.00 seconds. 
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.
New Types of Boundary Conditions for Solution of Fluid Structure Interaction Problems and their Implementation in Commercial Simulation Software
Pohanka, Lukáš ; Pochylý, František (referee) ; Zapoměl, Jaroslav (referee) ; Rudolf, Pavel (referee) ; Malenovský, Eduard (advisor)
New approach for computational modeling of the dynamic behavior of elastic body immersed in incompressible viscous stagnant fluid is described in this work. It is based on determination of added effects (added mass and added damping). This effects are inserted into computational model and it replace influence of the fluid. Commonly used commercial computational software may be used. Approach is based on assumption appropriate for the linear flow. Two pressure field are determined. One for movement of the unite acceleration of the fluid boundary and the second for unite velocity. Nonlinear model (Navier-Stokes equation in ALE form) had to be used for determination of the added damping, hence results are valid only for pre-selected amplitude of vibration.
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.
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.
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.
Comparison of time semi-discretization approaches for DGM solution of linear elasticity problem
Kosík, Adam ; Feistauer, M. ; Hadrava, Martin
The goal of the paper is to compare the application of the space-time discontinuous Galerkin method (STDGM) to other time discretization schemes on several simple model problems. We present a comparison of the numerical methods on the backwards Euler formula, the second order backward-difference formula and the Newmark scheme.
Space-time discontinuous Galerkin method for the problem of linear elasticity
Hadrava, Martin ; Kosík, A. ; Feistauer, M.
This paper describes the space-time discontinuous Galerkin method (STDGM) applied to the problem of dynamic linear elasticity. In contrast to standard applications of the DGM to non-stationary problems, the main concept of the discontinuous Galerkin method – discontinuous piecewise polynomial approximation – is applied both in space and in time and hence a more robust and accurate scheme is obtained.
Modelling of the airflow through vocal folds
Prokopova, J. ; Feistauer, M. ; Kučera, V. ; Horáček, Jaromír
The work introduces implementation of numerical techniques: the ALE (Arbitrary Lagrangian-Eulerian) method and the discontinuous Galerkin finite element method for solving the problem of the airflow through the human vocal folds. The viscous compressible flow in time-dependent domains was solved u by using our own program code based on the finite element approximation.

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