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Modelled pressure pulsations in a fluid with the influence of a second viscosity
Dzjamko, Vladislav ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The aim of this thesis is to determine the value of the speed of sound and the second dynamic viscosity of the fluid using numerical optimization of analytical model. Theoretically, the speed of sound and the second viscosity can be determined from three measured pressure waveforms in time along the length of the tube, while the speed of sound is traced to determine the correctness of the result. The thesis is divided into seven successive chapters. The first two define all the necessary concepts and the 1D analytical model used. The following chapters deal with the design of the experiment, data evaluation and numerical optimization of the search parameters in the frequency domain.The range of measured frequencies was from 1 kHz to 20,59 kHz. Einstein´s notation is used this this thesis. All graphs associated with the analytical model and the evaluation of the results are created in Matlab. The optimization functions fminsearch and lsqnonlin are used to evaluate the speed of sound and the second viscosity, however the fminsearch function overestimates the magnitude of the second viscosity. The thesis includes the calculation of the problem using Ansys and the subsequent comparison of all results.
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Damping of pressure pulsations and noise reduction in pipeline systems
Čepl, Ondřej ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The diploma thesis deals with pressure pulsations in pipeline system with dynamic muffler. There is presented original geometry of side-branch resonator. Pressure pulsations are solved by a created mathematical model, numerical simulations and verified by an experimental approach. The influence of dynamic and bulk viscosity is involved in derived governing equations. A system of nonlinear equations is solved by genetic algorithm and frequency dependent relationship of bulk viscosity of air is determined afterwards. The correct function of used pressure sensors is tested. The processing of experimental data is performed by the fast Fourier transform with coherent sampling. Finally, a comparison of analytical, numerical and experimental approaches is introduced for different geometric variants of presented muffler.
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Properties of fluids
Dzjamko, Vladislav ; Štefan, David (referee) ; Himr, Daniel (advisor)
The aim of this thesis is to present the basic equations describing the behaviour of fluids and to describe the substance characteristics that are present in them. The thesis is divided into four successive chapters, the first two of which explain the causes and consequences of the various fluid properties. The following chapter is devoted to equations and their derivation. Finally, the content of the thesis includes a description of some methods for determining selected material constants.
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Properties of fluids
Dzjamko, Vladislav ; Štefan, David (referee) ; Himr, Daniel (advisor)
The aim of this thesis is to present the basic equations describing the behaviour of fluids and to describe the substance characteristics that are present in them. The thesis is divided into four successive chapters, the first two of which explain the causes and consequences of the various fluid properties. The following chapter is devoted to equations and their derivation. Finally, the content of the thesis includes a description of some methods for determining selected material constants.
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Damping of pressure pulsations and noise reduction in pipeline systems
Čepl, Ondřej ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The diploma thesis deals with pressure pulsations in pipeline system with dynamic muffler. There is presented original geometry of side-branch resonator. Pressure pulsations are solved by a created mathematical model, numerical simulations and verified by an experimental approach. The influence of dynamic and bulk viscosity is involved in derived governing equations. A system of nonlinear equations is solved by genetic algorithm and frequency dependent relationship of bulk viscosity of air is determined afterwards. The correct function of used pressure sensors is tested. The processing of experimental data is performed by the fast Fourier transform with coherent sampling. Finally, a comparison of analytical, numerical and experimental approaches is introduced for different geometric variants of presented muffler.
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