The aim of this master’s thesis is to determine the torque momentum of the jet deflector of the Pelton turbine using a two-phased CFD simulation. The reason for determining the moments is the inaccurate formula according to a standard, whose results are assumed to be too excessive. The first part is devoted to theory of Pelton turbine and its main components. The second part contains the design of deflector, explanation of the used k- turbulence method and the Volume of Fluid two-phased flow modeling method. The results of the simulation are presented at the end of the thesis.

The thesis is focused on the design of a scintillation detector with one screen for environmental scanning electron microscope. At the beginning of the work is an introduction to microscopy. Further work is focused on the description of ESEM microscope and a scintillation detector. The following chapter is devoted to the dynamics of flow. They list the types of flow and mathematical description of equations. The next chapter is about using the software and the way of solution of flow. In the following chapter describes a proposal of the diaphragm and extraction method of the detector area. They are described some of type aperture. The last chapter is the conclusion, where the work is summarized.

Planing hull is one solution to break the speed barrier of conventional hull, but as the boat reaches a high speed, massive whisker spray will be developed and attached to the hull, which causes a notable resistance increase. A Swedish company Peterstep invented an innovative spray deflector that can deflect the spray backwards and harvest kinetic energy from the spray.In the 2019 spray deflector project, many tests were done in Davison Laboratory Towing Tank, and there is a trim angle difference between plated and non-plated hulls. To investigate possible reasons, more tests are implemented in this project. According to the test results, the reason is determined as the different roughness of the hull and bottom due to differences in materials. Also, the tape for sealing the seam between hull and bottom plate affects the sharpness of the hard chine, thereby hindering the flow separation.The model used in previous experiments is no longer suitable for the further investigation. The modular design caused the different running position of plated and non-plated hull. In addition, the hull is too slender for the wave test. Therefore, a new model is needed to satisfy the new objectives of experiments. In this paper, the detailed design is surrounded by design aims and restrictions, such as increase spray resistance and avoid porpoising.There are few researches on HSC free running model test. To investigate the performance of the spray deflector in the test environment more similar to reality, a free running model with propulsion and steering system is necessary. The preliminary design, component selection and testing plan are outlined in this paper. / Planande skrov är en lösning för att bryta hastighetsbarriären hos ett konventionellt skrov, men när båten når hög hastighet kommer omfattande whisker spray att utvecklas på skrovet, vilket orsakar en anmärkningsvärd ökning av motståndet. Ett svenskt företag Peterstep har utvecklat en innovativ sprutdeflektor som kan avleda sprayen bakåt och skörda kinetisk energi från sprayen.Under sprutdeflektorprojektet 2019 gjordes många tester i Davison Laboratorys släpränna och det noterades en oönskad trimvinkelskillnad mellan modeller där skrovet byggts i en del eller med ett steg som fyllts igen med en bottenplatta. För att undersöka möjliga skäl till detta implementeras nya tester i detta projekt. Enligt testresultaten bestäms orsaken som skrovets och bottenplattans olika jämnhet på grund av materialskillnader. Även tejpen för tätning av sömmen mellan skrov och bottenplatta påverkar skärpan i slaget och hindrar därmed flödets avlösning.Modellen som använts i tidigare experiment är inte lämplig för fortsatt utredningen. Den modulära designen orsakade olika gångläge beroende på hur skroven hade byggts upp. Dessutom är skrovet för smalt för vågproven. Det behövs därför en ny modell för att uppfylla målen med experimenten.I det här arbetet har designen ytterligare designmål och begränsningar, som att mäta sprutmotståndet och att undvika porpoising.Det finns få undersökningar om HSC-test med frigående modeller. För att undersöka sprutdeflektorers prestanda i testmiljö som liknar verkligheten är det nödvändigt med en frigående modell med eget framdrivnings- och styrsystem. Den preliminära designen, komponentvalet och testplanen beskrivs i detta dokument.

This dissertation proposes, studies and experimentally demonstrates novel liquid crystal (LC) optics to solve challenging problems in RF and photonic signal processing, freespace and fiber optic communications and microscopic imaging. These include free-space optical scanners for military and optical wireless applications, variable fiber-optic attenuators for optical communications, photonic control techniques for phased array antennas and radar, and 3-D microscopic imaging. At the heart of the applications demonstrated in this thesis are LC devices that are non-pixelated and can be controlled either electrically or optically. Instead of the typical pixel-by-pixel control as is custom in LC devices, the phase profile across the aperture of these novel LC devices is varied through the use of high impedance layers. Due to the presence of the high impedance layer, there forms a voltage gradient across the aperture of such a device which results in a phase gradient across the LC layer which in turn is accumulated by the optical beam traversing through this LC device. The geometry of the electrical contacts that are used to apply the external voltage will define the nature of the phase gradient present across the optical beam. In order to steer a laser beam in one angular dimension, straight line electrical contacts are used to form a one dimensional phase gradient while an annular electrical contact results in a circularly symmetric phase profile across the optical beam making it suitable for focusing the optical beam. The geometry of the electrical contacts alone is not sufficient to form the linear and the quadratic phase profiles that are required to either deflect or focus an optical beam. Clever use of the phase response of a typical nematic liquid crystal (NLC) is made such that the linear response region is used for the angular beam deflection while the high voltage quadratic response region is used for focusing the beam. Employing an NLC deflector, a device that uses the linear angular deflection, laser beam steering is demonstrated in two orthogonal dimensions whereas an NLC lens is used to address the third dimension to complete a three dimensional (3-D) scanner. Such an NLC deflector was then used in a variable optical attenuator (VOA), whereby a laser beam coupled between two identical single mode fibers (SMF) was mis-aligned away from the output fiber causing the intensity of the output coupled light to decrease as a function of the angular deflection. Since the angular deflection is electrically controlled, hence the VOA operation is fairly simple and repeatable. An extension of this VOA for wavelength tunable operation is also shown in this dissertation. A LC spatial light modulator (SLM) that uses a photo-sensitive high impedance electrode whose impedance can be varied by controlling the light intensity incident on it, is used in a control system for a phased array antenna. Phase is controlled on the Write side of the SLM by controlling the intensity of the Write laser beam which then is accessed by the Read beam from the opposite side of this reflective SLM. Thus the phase of the Read beam is varied by controlling the intensity of the Write beam. A variable fiber-optic delay line is demonstrated in the thesis which uses wavelength sensitive and wavelength insensitive optics to get both analog as well as digital delays. It uses a chirped fiber Bragg grating (FBG), and a 1xN optical switch to achieve multiple time delays. The switch can be implemented using the 3-D optical scanner mentioned earlier. A technique is presented for ultra-low loss laser communication that uses a combination of strong and weak thin lens optics. As opposed to conventional laser communication systems, the Gaussian laser beam is prevented from diverging at the receiving station by using a weak thin lens that places the transmitted beam waist mid-way between a symmetrical transmitter-receiver link design thus saving prime optical power. LC device technology forms an excellent basis to realize such a large aperture weak lens. Using a 1-D array of LC deflectors, a broadband optical add-drop filter (OADF) is proposed for dense wavelength division multiplexing (DWDM) applications. By binary control of the drive signal to the individual LC deflectors in the array, any optical channel can be selectively dropped and added. For demonstration purposes, microelectromechanical systems (MEMS) digital micromirrors have been used to implement the OADF. Several key systems issues such as insertion loss, polarization dependent loss, wavelength resolution and response time are analyzed in detail for comparison with the LC deflector approach. A no-moving-parts axial scanning confocal microscope (ASCM) system is designed and demonstrated using a combination of a large diameter LC lens and a classical microscope objective lens. By electrically controlling the 5 mm diameter LC lens, the 633 nm wavelength focal spot is moved continuously over a 48 [micro]m range with measured 3-dB axial resolution of 3.1 [micro]m using a 0.65 numerical aperture (NA) micro-objective lens. The ASCM is successfully used to image an Indium Phosphide twin square optical waveguide sample with a 10.2 [micro]m waveguide pitch and 2.3 [micro]m height and width. Using fine analog electrical control of the LC lens, a super-fine sub-wavelength axial resolution of 270 nm is demonstrated. The proposed ASCM can be useful in various precision three dimensional imaging and profiling applications.

The terminations and the joints are the basic accessories of the power cables. Power cables require electrical stress control when terminated. Since there are different types of terminations, the analysis should be done to choose the proper method for electric field control problem at the terminations. Throughout this study two different types of termination methods are investigated by using the finite element analysis program (ANSYS): Stress Controlled Termination Model with Deflector and Stress Control Tube (SCT). The results are compared with those obtained for a cable without stress control model termination. The numerical calculations are also compared with the measurements obtained by an experimental model: the electrolytic tank model.

The present work deals with electron microscopy, electron microscopy primarily environmental. The main task of the work will draft the optimal shape of the differentially pumped chamber, dividing the pressure difference between tube and chamber with sample for a new concept of an electron microscope. By ANSYS Fluent will be analyzed pumping gas. Subsequently, according to the results obtained will be a modified form of the differential Chamber and to achieve the lowest gas pressure on the track of the electron beam.

A major limitation of acousto-optic (AO) leaky-mode modulator based holographic displays is their inability to present full-parallax. We propose that full-parallax capabilities can be bestowed on these displays by integrating an electro-optic (EO) phased array into the architecture. We validated this concept by rendering computational models and by fabricating and testing a basic two-axis AO/EO deflector prototype in lithium niobate. This was, to our knowledge, the first instantiation of an integrated, hybrid AO/EO deflector. The prototype had a 6° deflection range along the AO-axis, and a 3° deflection range along the EO-axis. A series of models provide us with a clear path forward for optimizing this deflector. They suggest that an AO/EO modulator with an EO deflection range of 24.5° and that requires less than 7.5 V can be fabricated within the limitations of standard photolithography.

The aim of the project behind this report is to gain an understanding for the design criteria of launch pad flame deflectors used for launching rockets. This report presents an overview of the underlying phenomena, and then tackles the issue of estimating noise levels that come about during lift-off. Semi-empirical methods are used to accomplish this, and the same basic processes as those presented in a 1971 NASA report are used. The underlying assumptions and approximations used in this report are analysed, and a number of modifications are suggested. The results of these modifications are presented in comparison to the original model as well as data taken from the Ares I-X launch. It is found that the suggested methodology tends to overpredict where the SP-8072 method underpredicts, and that additional considerations regarding launch pad structure and water attenuation will need to be included for a more detailed understanding. Furthermore, the topic of acoustic reflectivity is investigated. It is demonstrated that this aspect is heavily dependent on the dimensions of the flame duct immediately downstream of the nozzle, and that further development is warranted. / Målet med detta projekt är att öka förståelsen för flamdeflektorer och vad som avgör utformningen av dessa. Rapporten presenterar en översikt av de fenomen och mekanismer som alstrar ljud, och fokuserar sedan på att beskriva hur dessa ljudnivåer uppskattas. Semi-empiriska metoder används, och de processer som presenteras i en NASA-rapport från 1971 tillämpas. De antaganden och approximationer som används i denna analyseras, och en rad ändringar föreslås. Resultaten från dessa ändringar presenteras tillsammans med den oförändrade modellen tillsammans med uppmätt data från uppskjutningen av Ares I-X. Den föreslagna modellen visar sig överuppskatta där den oförändrade tenderar att underuppskatta. Ytterligare aspekter gällande uppskjutningsplattformens geometri samt den dämpande effekten vatten har behöver iakttas för en mer detaljerad modell. Akustisk reflektivitet och dess ljudbidrag undersöks. Det visas att denna aspekt beror starkt på dimensionerna för avgaskanalen direkt nedströms från dysan. Det finns därmed anledning för vidareutveckling av denna modell.

Une description des différentes configurations d’interaction ayant lieu dans les matériaux usuellement employés dans le domaine acousto-optique est proposée. Un exemple d’application illustre les caractéristiques déterminantes propres à chaque fonction que permet l’interaction acousto-optique, à savoir la modulation, la déviation, le décalage en fréquence et le filtrage d’un faisceau optique. Cette thèse est plus particulièrement consacrée aux interactions acousto-optiques anisotropes dans le cristal de Paratellurite, matériau majoritairement employé pour les applications de déflexion et de filtrage de par ses qualités photo-élastiques remarquables et son large domaine de transparence optique. Ces propriétés optiques, acoustiques et acousto-optiques sont décrites en détail. Nous nous intéressons plus particulièrement aux caractéristiques de l’interaction NPM (Narrow Phase Mismatch) et TPM (Tangent Phase Mismatch), respectivement employées pour le filtrage et la déflexion. Ceci nous conduit à l’étude de la bande passante spectrale d’un déflecteur et de sa potentielle application en tant que réseau de diffraction à bande passante et périodicité spatiale modulable. Ensuite nous proposons la mise en cascade d’un déflecteur et d’un filtre dans le but de concevoir un décaleur de fréquence variable à faible décalage. Enfin, nous proposons une configuration originale pour répondre aux contraintes d’utilisation rencontrées avec l’interaction NPM pour les applications de filtrage. La conception et la réalisation d’un composant multiélectrodes à interaction double est alors présentée dans la gamme spectrale [400; 650 nm]. La configuration proposée permet à la fois de réduire de 50% l’intensité des lobes secondaires tout en homogénéisant la bande passante optique du filtre sur sa bande spectrale de travail. / The different configurations of acousto-optic interactions taking place in usual employed materials are presented. For each function (modulation, deflection, shifting and filtering), an exemple of application highlights the decisive characteristics of the component. This thesis is particularly devoted to the anisotropic interactions occuring in Paratellurite crystal. Such material is widely used for filtering and deflection applications due to its high figure of merit and also for its large optical transparency domain, from Ultra-Violet to Infra-Red. Optical, acoustical and acoustooptical properties of Paratellurite cristal are detailed. More precisely, we are interested in anisotropic interactions, in particular NPM (Narrow Phase Mismatch) and TPM (Tangent Phase Mismatch), respectively employed for Acousto-Optic Tunable Filters (AOTF) and Acousto-Optic Deflectors (AOD). This leads to the study of the optical bandwidth of a deflector with a potential application as a tunable transmissive grating beam splitter for multiple laser line separation. Then, we propose to cascade an AOTF with an AOD in order to get a wide bandwidth tunable optical low frequency shifter. Finally, we present the design and fabrication of a multi-transducer component based on dual anisotropic interaction in the visble spectral range, from 400 to 650 nm. A significative reduction of sides lobes is observed (-50%) with an homogenisation of the optical bandwidth of the filter on its spectral working range.

The noise of a rocket engine is a complex and complicated phenomenon which has been studied for more than half a century [1]. There are many sources to this noise, but due to its great potential impact to the surrounding structures, including the vehicle itself, it is important to have a model to estimate the acoustic environment the engine produces. This estimation can be used for the design of a launch pad or a flame deflector. Such a model was developed and then tested, by measuring the noise levels with six microphones at Rocket Factory Augsburg´s Vertical Test Stand at Esrange Space Centre. Three out of six microphones yielded valuable data. A comparison between the estimated and measured noise was then conducted which showed similar trends. The peak frequency in the estimation was in the order of 1 kHz. A sensitivity study was made to investigate the difference in Sound Power Level (SPL) when the engine and test stand parameters were adjusted. The parameters with the greatest effect on the SPL are the Mach number, thrust, potential core length, and impingement distance. The difference in SPL between the estimation and measured noise is 0-20 dB with a lower difference at lower frequencies and a higher difference at higher frequencies. The difference was higher when comparing the estimation to the test with an overpowered engine, with differences of up to 20 dB higher than the estimation in the upper frequencies. Differences with nominal engine data was up to 15 dB higher than the estimation, constrained to lower frequencies. Above 30% of the peak frequency, the noise was consistently lower than the estimation. The estimation can be concluded to likely be conservative at higher frequencies, further testing or a new estimation is necessary with accurate engine data. / Ljudet från en raketmotor är ett komplext och komplicerat fenomen som har studerats i mer än ett halvt sekel [1].Det finns många källor till det ljudet, men på grund av risken att det skadar omgivande strukturer, inklusive raketen, är det viktigt att ha en modell för att estimera ljudmiljön motorn produceras. Estimeringen kan användas för att designa en uppskjutningsramp eller en flammdeflektor. En sådan modell var utvecklad och testad genom att göra ljudmätningar med sex mikrofoner på Rocket Factory Augsburg´s testanläggning på Esrange Space Centre. Tre av sex mikrofoner gav värdefull data. En jämförelse gjordes mellan det estimerade och uppmätta ljudet vilket visade liknande trender. Toppfrekvensen i estimeringen var i storleksordningen 1 kHz. En känslighetsstudie gjordes för att undersöka skillnaden i ljudnivån (SPL) när motorns och testanläggningens parametrar justerades. Parametrarna med störst påverkan på ljudnivån var Mach numret, drivkraft, längden av flamman och avståndet till deflektorn. Ljudskillnaden mellan det estimerade och uppmätta ljudet var mellan 0-20 dB med mindre skillnad på lägre frekvenser och större skillnad på högre frekvenser. Skillnaden var större vid jämförelse mellan estimering och testet med en kraftigare motor, med skillnader på upp till 20 dB över estimeringen på de högre frekvenserna. Skillnaderna för nominell motordata var upp till 15 dB högre än estimeringen, begränsat till lägre frekvenser. Över 30% av toppferkvensen var ljudet konsekvent lägre än estimeringen. Estimeringen kan sannolikt konstateras vara konservativ på högre frekvenser, ytterligare tester eller estimeringar behövs med exakt motordata.