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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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From tornado to hydraulic turbine
Jízdný, Martin ; Rinka, Lukáš (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with vortex motion and contains two main parts. The first part refers to the principles of creation and evolution of vortex motion in nature and in technological applications. In both of these fields it is possible to find positive and negative impacts of vortex motion which influence the world significantly. The second part of this bachelor thesis refers to an experiment which main goal was to verify some selected qualitites of vortex motion and to determine hypothesis based on measurements. The final part of the experiment deals with the different methods of making vortex motion visible in laboratory conditions.
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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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|
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From tornado to hydraulic turbine
Jízdný, Martin ; Rinka, Lukáš (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with vortex motion and contains two main parts. The first part refers to the principles of creation and evolution of vortex motion in nature and in technological applications. In both of these fields it is possible to find positive and negative impacts of vortex motion which influence the world significantly. The second part of this bachelor thesis refers to an experiment which main goal was to verify some selected qualitites of vortex motion and to determine hypothesis based on measurements. The final part of the experiment deals with the different methods of making vortex motion visible in laboratory conditions.
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