|
|
Function of surge chamber
Březina, Michal ; Jandourek, Pavel (referee) ; Klas, Roman (advisor)
The thesis is focused on creation of the mathematical model for calculating the change of fluid volume and flow in surge tank and air chamber during the water hammer effect. The work also includes the derivation of the basic equations of hydrodynamics and the theory dealing with water hammer including the possibilities in protection of the pipeline system during this phenomenon.
|
|
|
Modification of Navier_Stokes equations asuming the quasi-potential flow
Navrátil, Dušan ; Pochylý, František (referee) ; Fialová, Simona (advisor)
The master's thesis deals with Navier-Stokes equations in curvilinear coordinates and their solution for quasi-potential flow. The emphasis is on detailed description of curvilinear space and its expression using Bézier curves, Bézier surfaces and Bézier bodies. Further, fundamental concepts of hydromechanics are defined, including potential and quasi-potential flow. Cauchy equations are derived as a result of the law of momentum conservation and continuity equation is derived as a result of principle of mass conservation. Navier-Stokes equations are then derived as a special case of Cauchy equations using Cauchy stress tensor of Newtonian compressible fluid. Further transformation into curvilinear coordinates is accomplished through differential operators in curvilinear coordinates and by using curvature vector of space curve. In the last section we use results from previous chapters to solve boundary value problem of quasi-potential flow, which was solved by finite difference method using Matlab environment.
|
|
|
The force of water jet on a flat surface
Kasal, Milan ; Soukup, Lubomír (referee) ; Fic, Miloslav (advisor)
This bachelor thesis discusses about the theory of fluid mechanics. In the first part of work are listed the basic hydrodynamic laws for ideal and real fluid. Further there was derived force acting on the surface. The second part is devoted to the practical use of force water jet to generate electricity and cutting of material. The objective of the last section, was practical verification of derived relations during laboratory measurements.
|
|
|
Damping of Pressure Pulsations in Elastic Pipes
Panko, Martin ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
This diploma thesis deals with numerical simulation of pressure pulsations in elastic pipes. Continuity relation of fluid in elastic pipes, when calculating some damping in pipe material, is derived into practice. Rheological model of such a pipe corresponds to Voigt (Kelvin) model. For analysing dynamic effects in time periods are used numerical methods that deal with flow of compressible fluid: FTCS, Lax-Friedrichs and Lax-Wendroff method. The numerical results are confronted with the experiment. During the experiment simulation the method considers speed of sound in liquid like a function of pressure. This diploma thesis lays partial principles for finding elastic constants for describing dynamic characteristics of elastic pipes by measuring the pressure pulsations.
|
|
|
Mathematical models in hydromechanics (and aerodynamics)
Ježková, Jitka ; Zatočilová, Jitka (referee) ; Nechvátal, Luděk (advisor)
Bachelor thesis is a summarizing text which deals with the state and the motion of ideal liquid and gas. The main goal is to derive Euler equations describing the flow of fluids. From these equations we can obtain Bernoulli equation that is directly used to solve problems of fluid flow. The next step is to derive the continuity equation expressing the fact that the mass is preserved in the system. In the case of ideal gas the state equation of ideal gas is added and therefore solutions of various types of tasks of hydrodynamics and aerodynamics can be achieved.
|
|
|
Unsteady flow in pipeline
Šrenk, David ; Fialová, Simona (referee) ; Himr, Daniel (advisor)
The thesis deals with unsteady flow in the pipeline. Only one component of velocity is dominant in piping, so the problem is simplified to one-dimensional. Bachelor thesis has an analytical basis in partial differential equations of hyperbolic type. The problem and types of numerical methods are also numerically described. The numerical methods describe the boundary conditions and properties of the given methods.
|
|
|
Immersed boundary methods in air-flow models
Benešová, Stanislava ; Brechler, Josef (advisor) ; Hron, Jaroslav (referee)
This work focuses on the immersed boundary methods and their aplications to modeling flow in urban areas. In the first part Navier-Stokes equations are derived. In the second part we describe the main priciples of the immersed boundary methods. Two main groups of methods are introduced accompanied by examples. Based on the properties of these methods one method is selected which is suitable to describe the geometry in the modeling of airflow in urban areas. The method MIB from the article Mark et al. (2008) is chosen. This method is compared with the method introduced in the article Kim et al. (2001). Both methods are described in detail and compared according to several criteria in the third chapter. Such a criterion is the accuracy of the continuity equation. Simulations of a several test problems were carried out for the purpose of comparison of the chosen methods. Flow around a circular cylinder and a square cylinder for Reynolds numbers of 10 and 30 is solved. The divergence value of~the~velocity field in the modeled area was observed during the calculation of both methods. The results yields that MIB method solves the continuity equation more accurate.
|
|
|
Modification of Navier_Stokes equations asuming the quasi-potential flow
Navrátil, Dušan ; Pochylý, František (referee) ; Fialová, Simona (advisor)
The master's thesis deals with Navier-Stokes equations in curvilinear coordinates and their solution for quasi-potential flow. The emphasis is on detailed description of curvilinear space and its expression using Bézier curves, Bézier surfaces and Bézier bodies. Further, fundamental concepts of hydromechanics are defined, including potential and quasi-potential flow. Cauchy equations are derived as a result of the law of momentum conservation and continuity equation is derived as a result of principle of mass conservation. Navier-Stokes equations are then derived as a special case of Cauchy equations using Cauchy stress tensor of Newtonian compressible fluid. Further transformation into curvilinear coordinates is accomplished through differential operators in curvilinear coordinates and by using curvature vector of space curve. In the last section we use results from previous chapters to solve boundary value problem of quasi-potential flow, which was solved by finite difference method using Matlab environment.
|
|
|
Unsteady flow in pipeline
Šrenk, David ; Fialová, Simona (referee) ; Himr, Daniel (advisor)
The thesis deals with unsteady flow in the pipeline. Only one component of velocity is dominant in piping, so the problem is simplified to one-dimensional. Bachelor thesis has an analytical basis in partial differential equations of hyperbolic type. The problem and types of numerical methods are also numerically described. The numerical methods describe the boundary conditions and properties of the given methods.
|
|
|
Immersed boundary methods in air-flow models
Benešová, Stanislava ; Brechler, Josef (advisor) ; Hron, Jaroslav (referee)
This work focuses on the immersed boundary methods and their aplications to modeling flow in urban areas. In the first part Navier-Stokes equations are derived. In the second part we describe the main priciples of the immersed boundary methods. Two main groups of methods are introduced accompanied by examples. Based on the properties of these methods one method is selected which is suitable to describe the geometry in the modeling of airflow in urban areas. The method MIB from the article Mark et al. (2008) is chosen. This method is compared with the method introduced in the article Kim et al. (2001). Both methods are described in detail and compared according to several criteria in the third chapter. Such a criterion is the accuracy of the continuity equation. Simulations of a several test problems were carried out for the purpose of comparison of the chosen methods. Flow around a circular cylinder and a square cylinder for Reynolds numbers of 10 and 30 is solved. The divergence value of~the~velocity field in the modeled area was observed during the calculation of both methods. The results yields that MIB method solves the continuity equation more accurate.
|
guest ::
