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Extension of Centrifugal Compressor Operational Stability
Růžička, Miroslav ; Třetina, Karel (referee) ; Kmoch, Petr (referee) ; Klement, Josef (advisor)
Centrifugal compressors with high pressure ratio are widely used in small aircraft turbine engines and turbocharges. At high rotational speeds they have narrow stable operating region and commonly used impellers with back swept blades are not able to ensure requested stability. In order to achieve wider stable operating region, some other anti-surge measures can be used, such as an Internal Recirculation Channel (IRC) located in compressor impeller inlet. This thesis deals with an investigation of IRC influence on centrifugal compressor operational parameters. As a first, the various recirculation channel geometry was studied by using of CFD analysis on simplified computational models. Those geometry, which indicated best results in terms of mass flow and looses in channel were used for testing on a model test device. Subsequently the same geometry was tested on real centrifugal compressor in experimental turbine engine to verify influence of IRC on compressor performance map – pressure ratio and efficiency. Simultaneously the CFD analyses of IRC with a 3D model of compressor impeller were performed and results compared with those, gained from measurement on model and compressor. In addition the measurement of flow field downstream the recirculation channel outlet slot with using of 3-hole pressure probe was performed and compared with flow velocity profiles evaluated from numerical simulations.
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3D Physics Toolbox with Haptics Support
Čermák, Jakub ; Kmoch, Petr (advisor) ; Horáček, Jan (referee)
The main goal of this thesis is to create software which would allow a user to simulate and study physical processes in systems of mass particles, which follow laws of classical mechanics and can collide together. The simplicity and easiness of control was emphasized, which corresponds to support of haptic devices, which can be used both for influencing running simulation and creation of the scene. It is possible to change parameters in physical properties of objects and environment (like gravitation or air density) and also to visualize affecting forces and other properties. It allows the user to explore physical processes. This work uses knowledge from many fields - mass particle mechanics, numerical integration used for application of physical laws, algorithms for effective collision detection and haptic interaction and force rendering.
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Point Primitives on GPU
Skotáková, Jana ; Pelikán, Josef (advisor) ; Kmoch, Petr (referee)
In recent years representation of objects based on point primitives receives more interest. This thesis presents possibilities of processing of point-sampled models. It gives an overview of algorithms that can be used in solving problems like deformation or animation of point-sampled models. There is also described how such models can be obtained. In the following part Level Of Detail is presented with regard to point-sampled models. There are given basic methods and factors used for the LOD selection. Furthermore, there is proposed and implemented transfer of parts of the selected LOD generating algorithm to GPU. This keeps CPU available for other parts of the algorithm or even other tasks. DirectX 10 is used for the GPU programming. DirectX 10 uses the new model of graphic pipeline that enables the transfer of more parts of algorithm to GPU.
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Rendering Planetary Atmospheres in Real-Time
Elek, Oskár ; Kmoch, Petr (advisor) ; Maršálek, Lukáš (referee)
In the field of photorealistic rendering of physical phenomena, the rendering of atmospheric light scattering takes a very important place. Realtime rendering of sky and atmosphere in general is essential for all outdoor computer games, various simulators, virtual worlds or even for animated movies. It is a very difficult task, but thanks to the advancement of dedicated graphics hardware we can reach it today. In my thesis I present an accurate and fast method for real-time rendering of planetary atmospheres. This is achieved by precomputing complex single-scattering equations into a set of lookup tables. The correct atmospheric colour values are then fetched from these in the fragment shader. The presented method is then implemented in a program that is capable of rendering realistic atmosphere in hundreds of FPS.
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Particle systems
Růžička, Martin ; Pelikán, Josef (advisor) ; Kmoch, Petr (referee)
The presented work deals with the issue of particles. It aims to offer a system for particle creation, simulation and visualization. The introductory part of the paper is devoted to design a physical model. The physical model particularly stresses a fast and at the same time plausible approximation of physical laws. Afterwards, it deals with methods of describing the particle behavior. In order to achieve the highest possible flexibility, a scripting interface is used. The conclusion then describes the visualization of the final particles itself. It is realized using the designed extension of the OpenGL graphic library. The results of the work can be seen in an enclosed application which demonstrates the possibilities of the designed particle systems.
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Simulating Hair with the Loosely-Connected Particles Method
Soták, Šimon ; Kmoch, Petr (advisor) ; Wilkie, Alexander (referee)
This thesis presents an implementation of the Loosely Connected Particles (LCP) method of hair animation proposed by Bando et al. We updated the method with several modern approaches. Firstly, we implemented two variations of parallel processing for the simulation which di er in work distribution among threads. The results indicate that work is distributed evenly, and thus dynamic distribution is not needed. Secondly, we applied the Deep Opacity Maps method of hair shadowing on the LCP and introduced alpha thresholding to eliminate artifacts. We supply a clean user interface for parameter tweaking with instant response and an easy-to-use interface for cutting hair using mouse controls. We discuss the suitability of using C# with .NET for developing a performance-heavy application.
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Real-time Fur Rendering
Berger, Martin ; Kmoch, Petr (advisor) ; Sloup, Jaroslav (referee)
Rendering of fur is an important area of computer graphics, because visually convincing fur is essential for realism of games and computer generated imagery. This thesis presents a novel technique for fur rendering based on a previously published method for grass rendering. The technique works by tracing a ray at each pixel through the fur volume with implicitly de ned slices mapped with fur texture. A detailed analysis with performace tests, comparison with another state-of-the-art technique, and evaluation of applicability is presented along with a demonstration program.
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Procedural generation and realtime rendering of planetary bodies
Kahoun, Martin ; Horáček, Jan (advisor) ; Kmoch, Petr (referee)
The presented work deals with procedural generation of planetary bodies and their rendering in realtime. We take a closer look on one of the available methods and we try to improve the visual quality of produced models. We don't consider geophysical correctness of the planetary surface during the generation, nor we do any physical simulations to create the planets. We present what is possible by using several numbers, noise generator and fractal functions. We emphasize aesthetic feeling, and we try to other similar effect to the Google Earth, i.e., the opportunity to view a planet from high altitudes as well as a close-up zoom to the surface. Besides, we allow exporting generated models into external format suitable for processing in a 3D modelling software. We also support saving planetary parameters and their loading into the application.
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