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Internet schematic editor
Popelka, Lukáš ; Biolek, Dalibor (referee) ; Kadlec, Jaroslav (advisor)
The diploma thesis deals with creating of electronic schematics in editor using web interface. The editor generates electrical circuit text file according to Spice netlist specification. The program has been created in Java and takes an advantage of object oriented programming language. The editor is a part of a web page and is executable as an applet. The diploma thesis describes a programming language selection, program layout and implementation. Thesis contains programming code examples, window illustration and component drawings. Depth-first search algorithm has been used for nodes number assignment. An OrCAD PSpice reference guide was used for netlist.
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Shear layer-synthetic jet interaction.Qualitative solution
Falta, Jiří ; Maršík, František (advisor) ; Popelka, Lukáš (referee) ; Uruba, Václav (referee)
This thesis investigates possibilities of suppressing the boundary layer separation which is made by controling boundary layer stability. Orr-Sommerfeld equation is numerically solved for this purpose and its solution was tested on Blasius boundery layer which stability is described in many specialized publications. Transition to turbulence is found out by eN method. Single-variable description of velocity pro les on own surface, which is based on the aproximative properties of Falkner-Skan equation, was used. Process of transition on the aerofoil NACA 63-418 was solved as an example of using proposed computational programs.
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Shear layer-synthetic jet interaction.Qualitative solution
Falta, Jiří ; Maršík, František (advisor) ; Popelka, Lukáš (referee) ; Uruba, Václav (referee)
This thesis investigates possibilities of suppressing the boundary layer separation which is made by controling boundary layer stability. Orr-Sommerfeld equation is numerically solved for this purpose and its solution was tested on Blasius boundery layer which stability is described in many specialized publications. Transition to turbulence is found out by eN method. Single-variable description of velocity pro les on own surface, which is based on the aproximative properties of Falkner-Skan equation, was used. Process of transition on the aerofoil NACA 63-418 was solved as an example of using proposed computational programs.
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Internet schematic editor
Popelka, Lukáš ; Biolek, Dalibor (referee) ; Kadlec, Jaroslav (advisor)
The diploma thesis deals with creating of electronic schematics in editor using web interface. The editor generates electrical circuit text file according to Spice netlist specification. The program has been created in Java and takes an advantage of object oriented programming language. The editor is a part of a web page and is executable as an applet. The diploma thesis describes a programming language selection, program layout and implementation. Thesis contains programming code examples, window illustration and component drawings. Depth-first search algorithm has been used for nodes number assignment. An OrCAD PSpice reference guide was used for netlist.
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Visualisation of Boundary Layer Separation and Passive Flow Control on Airfoils and Bodies in Wind-Tunnel and In-Flight Experiments
Popelka, Lukáš ; Kuklová, J. ; Šimurda, David ; Součková, Natálie ; Matějka, Milan ; Uruba, Václav
Infrared camera, Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds numbers transition mechanism. Airfoils of Wortmann FX66 series and FX66 series wing-fuselage interaction, as well as modern airfoils and their wing-fuselage geometry were subject to study. The presence of previously identified structures in the CFD modelling, such as horse-shoe vortices, was confirmed in the flow.
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Numerical and experimental modelling of transition in a separated boundary layer on the NACA63A421 airfoil
Ďuriš, M. ; Popelka, Lukáš ; Příhoda, Jaromír ; Šimurda, David
The paper is concerned with numerical modelling of transition in a separated boundary layer. A transition model is based on the combination of empirical terms determining position of the transition and averaged Navier–Stokes equations closed by SST turbulence model. The model of transition is applied in computation of 2D flow past NACA63A421 airfoil. Computation is performed using commercial code Fluent 6.3.26, in which the transition model is implemented as a User-Defined-Function. Computed distributions of the pressure coefficient along the airfoil are verified by comparison with experimental data, which were obtained by measurements in a closed circuit wind tunnel at the constant Reynolds number and several angles of attack. The comparison proves the applicability of the implemented transition model.
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An influence of amplitude modulation of the synthetic jet to the flow
Matějka, M. ; Popelka, Lukáš
The paper deals with an experimental research of an active boundary layer control achieved by using periodic excitation of a synthetic jet. An influence of amplitude modulation of the synthetic jet flow control to the flow field of the wake was studied. It summarizes the influence of the basic factors that affect the design of the synthetic jet actuator. The principle of a flow control with and without amplitude modulation was used. Flow visualization of the flow field was done.
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PASSIVE CONTROL OF BOUNDARY LAYER TRANSITION AND SEPARATION
Popelka, Lukáš ; Matějka, M. ; Šimurda, David ; Součková, Natálie
Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds number transition mechanism. Airfoils of three Czech-designed sailplanes and their wing-fuselage interaction were subject to study. Experimental data were coupled with numerical modeling and synthesis gained. Effect of passive flow control devices - vortex generators - was surveyed, counter-rotating vortex generators and Zig-zag type turbulators were applied. Separation suppression was reached and consequent drag coefficient reduction of test aircrafts measured in flight. Investigation was further extended by PIV Time-Resolved technique.
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