Este trabalho descreve a utilização de um software livre educacional do interferômetro de Mach-Zehnder (IMZ), em português, como instrumento motivador, ilustrativo, de fácil manuseio e compreensão, para ajudar no ensino e aprendizagem de Física. Salientamos que este software educacional foi desenvolvido através de um projeto coordenado pelas professoras Fernanda Ostermann e Flávia Rezende, do Instituto de Física da Universidade Federal do Rio Grande do Sul (UFRGS) e da Universidade Federal do Rio de Janeiro (UFRJ) e foi utilizado como principal instrumento para introduzir conceitos fundamentais de física quântica em uma disciplina do curso Mestrado Profissional de Ensino de Física. No entanto, podemos dizer que esta foi a primeira vez que o IMZ foi aplicado a uma turma de professores não ligados profissionalmente à UFRGS. Em acréscimo ao software, foram elaborados e remodelados como produtos educacionais, textos de apoio e guias experimentais que poderão ser usados tanto por professores, como por alunos do Ensino Médio. Fenômenos ondulatórios foi o assunto explorado e um de seus subtemas, a interferência da luz, foi bastante enfatizada. Colocamos à disposição dos professores um material didático de fácil interpretação, podendo, também, ser utilizado com alunos do Ensino Médio. O desenvolvimento desse material tem caráter estratégico para que sirva de base a futuras transposições de temas da física quântica, em particular, o fenômeno da dualidade onda-partícula, para este nível de ensino. Este material de apoio e o software compreendem um curso de quarenta horas, para um grupo de seis professores da rede estadual, mais especificamente para os professores que lecionam Física, nas escolas que representam a 6ª Coordenadoria Regional de Educação (6ª CRE), com o apoio da mesma. O curso aconteceu em 2006, na Escola Estadual de Ensino Médio “Ernesto Alves de Oliveira”, em Santa Cruz do Sul, RS. Embasado na Teoria de Aprendizagem Significativa de Ausubel, o material servirá, também, como base ou conhecimento prévio para futuras investidas em outros temas relacionados à física quântica. O conteúdo da teoria ondulatória da luz, trabalhado sobre o aparato do interferômetro virtual de Mach-Zehnder proporcionou a interação entre o conhecimento novo (física quântica e dualidade ondapartícula, desenvolvida sobre o interferômetro virtual de Mach-Zehnder no regime quântico) e o prévio (teoria ondulatória da luz desenvolvida sobre o interferômetro virtual de Mach- Zehnder clássico), possibilitando uma aprendizagem significativa e dando sentido às novas informações. No decorrer do curso, ao analisarmos o comportamento e as atitudes dos professores, pudemos perceber que este assunto não é trabalhado no Ensino Médio, e que eles apresentam dificuldades em relação aos conceitos fundamentais da teoria. Entretanto, parte do grupo mostrou interesse em obter novos conhecimentos, pois em todos os encontros havia questionamentos relacionando novos conceitos com os pré-existentes. Enfim, o software gerou visível entusiasmo com as novas possibilidades de aulas “práticas”, com a aprendizagem dos novos conceitos e também a proposta de se avaliar com a utilização de mapas conceituais, estratégia desenvolvida por Novak. / In this work it is shown how the utilization of a free educational software can be useful as a motivating and illustrative tool to help the teaching and understanding of fundamental concepts on quantum mechanics. Besides being available also in Portuguese, the virtual Mach-Zehnder Interferometer (MZI) is easy to handle. The software has been developed under a project coordinated by Professor Ostermann (UFRGS) and Professor Rezende (UFRJ) and has been used as a main tool to introduce students from Mestrado Profissional em Ensino de Física to fundamental concepts on quantum physics. Here, it is reported the first time the software was used in an environment that is not university. Concepts of quantum physics were discussed in a 40 hours course given to a group of six secondary level school teachers in 2006. They were teachers working under the 6ª Coordenadoria Regional de Educação (6ª CRE). The course took place in Santa Cruz do Sul (RS) at Escola Estadual de Ensino Médio “Ernesto Alves de Oliveira”. In order to help the students with the software itself and physical concepts that could help the understanding of the simulations results, supporting materials like helping texts and experimental guides were prepared based on Ausubel framework. We were also concerned about an educational product that could also be helpful to secondary level school students. The texts are available in an easy language and straightforward physics. Although the number of students were relatively small, the group was representative in the sense it reproduces the reality of public secondary schools in Brazil. Physics is not, in general, taught by people that are graduated in Licenciatura em Física and the ones that are, are in general, not very well prepared. It was clear that no one in the group had enough confidence “to touch” subjects related to quantum physics in classes having the excuse this is a very difficult topic to overcome. Using optical physics as basis and the virtual MZI, we could see some enthusiasm when the students realize it is possible, for example, to discuss some concepts related to wave-particle duality without unreachable mathematics.

Lors de sa rentrée dans l’atmosphère d’une planète, un engin spatial subit un échauffement important dû aux frottements des gaz atmosphériques sur la paroi. Cette élévation de température conduit à une dégradation physico-chimique du bouclier thermique de l’objet constitué de matériaux composites. Un composite est constitué de divers matériaux qui s’ablatent différemment. Dans cette thèse, nous nous intéressons essentiellement à la fusion d’un matériau durant sa phase de rentrée atmosphérique. Nous sommes donc en présence de trois phases : solide, liquide et gaz. Pour simuler ce phénomène, des méthodes numériques robustes ont été mises au point pour calculer l’écoulement diphasique compressible autour de l’objet. Le couplage entre le solide et l’écoulement fluide a aussi été étudié. Les méthodes numériques développées durant cette thèse sont basées sur une approche volumes finis. Une stratégie de décomposition d’opérateurs est utilisée pour résoudre le modèle diphasique à cinq équations avec les termes de dissipation modélisant l’écoulement fluide. L’idée principale de cette décomposition d’opérateurs est de séparer les phénomènes acoustiques et dissipatifs des phénomènes de transport. Un traitement implicite de l’étape acoustique est réalisé tandis que l’étape de transport est résolue explicitement. Le schéma semi-implicite global est alors très robuste, conservatif et préserve les discontinuités de contact. Les conditions d’interface entre les domaines fluide et solide sont déduites des bilans de masse et d’énergie à la paroi. Le front de fusion est suivi explicitement grâce à une formulation ALE des équations. La robustesse de l’approche et l’apport de la formulation semi-implicite sont finalement démontrés grâce à des expériences numériques mono et bidimensionnelles sur maillages curvilignes mobiles. / During atmospheric re-entry phase, a spacecraft undergoes a sudden increase of the temperature due to the friction of atmospheric gases. This rise drives to a physical-chemical degradation of the thermal protective system of the object made of composite material. A composite is made of several materials with ablates differently. In this thesis, we mainly focus on the melting of an object during its re-entry phase. Therefore there are three phases: solid, liquid and gas phases. In order to simulate this phenomenon, robust numerical methods have been developed to compute a compressible multiphase flow. The coupling strategy between the solid and the fluid have also been studied. Solvers developed in the present work are based on Finite Volume Method. A splitting strategy is used to compute compressible two-phase flows using the five-equation model with viscous and heat conduction effects. The main idea of the splitting is to separate the acoustic and dissipative phenomena from the transport one. An implicit treatment of the acoustic step is performed while the transport step is solved explicitly. The overall scheme resulting from this splitting operator strategy is very robust, conservative, and preserves contact discontinuities. The boundary interface condition between the solid and the multiphase flow is enforced by mass and energy balances at the wall. The melting front is tracked explicitly using an ALE formulation of the equations. The robustness of the approach and the interest of the semi-implicit formulation are demonstrated through numerical simulations in one and two dimensions on moving curvilinear grids.

Dans cette thèse on s’intéresse à la simulation numérique d’écoulements des matériaux compressibles, voir fluides et solides élastiques. Les matériaux considérés sont décrits avec un modèle monolithique eulérian, fermé avec une loi d’état hyperélastique qui considère les différents comportements des matériaux. On propose un nouveau schéma de relaxation qui résout les écoulements compressibles dans des différents régimes, avec des nombres de Mach très petits jusqu’à l’ordre 1. Le schéma a une formulation générale qui est la même pour tous le matériaux considérés, parce que il ne dépend pas directement de la loi d’état. Il se base sur une discrétisation complétement implicite, facile à implémenter grâce à la linéarité de l’opérateur de transport du système de relaxation. La discrétisation en espace est donnée par la combinaison de flux upwind et centrés, pour retrouver la correcte viscosité numérique dans les différents régimes. L’utilisation de mailles cartésiennes pour les cas 2D s’adapte bien à une parallélisation massive, qui permet de réduire drastiquement le temps de calcul. De plus, le schéma a été adapté pour la résolution sur des mailles quadtree, pour implémenter l’adaptativité de la maille avec des critères entropiques. La dernière partie de la thèse concerne la simulation numérique d’écoulements multi-matériaux. On a proposé une nouvelle méthode d’interface “sharp”, en dérivant les conditions d’équilibre en implicite. L’objectif est la résolution d’interfaces physiques dans des régimes faiblement compressibles et avec un nombre de Mach faible, donc les conditions multi-matériaux sont couplées au schéma implicite de relaxation. / In this thesis we are concerned with the numerical simulation of compressible materials flows, including gases, liquids and elastic solids. These materials are described by a monolithic Eulerian model of conservation laws, closed by an hyperelastic state law that includes the different behaviours of the considered materials. A novel implicit relaxation scheme to solve compressible flows at all speeds is proposed, with Mach numbers ranging from very small to the order of unity. The scheme is general and has the same formulation for all the considered materials, since a direct dependence on the state law is avoided via the relaxation. It is based on a fully implicit time discretization, easily implemented thanks to the linearity of the transport operator in the relaxation system. The spatial discretization is obtained by a combination of upwind and centered schemes in order to recover the correct numerical viscosity in different Mach regimes. The scheme is validated with one and two dimensional simulations of fluid flows and of deformations of compressible solids. We exploit the domain discretization through Cartesian grids, allowing for massively parallel computations (HPC) that drastically reduce the computational times on 2D test cases. Moreover, the scheme is adapted to the resolution on adaptive grids based on quadtrees, implementing adaptive mesh refinement techinques. The last part of the thesis is devoted to the numerical simulation of heterogeneous multi-material flows. A novel sharp interface method is proposed, with the derivation of implicit equilibrium conditions. The aim of the implicit framework is the solution of weakly compressible and low Mach flows, thus the proposed multi-material conditions are coupled with the implicit relaxation scheme that is solved in the bulk of the flow.

A body in a hypersonic flow field will experience very high heating especially during re-entry. Conventionally this problem is tackled to some extent by the use of large angle blunt cones. At the cost of increased drag, the heat transfer rate is lower over most parts of the blunt body, except in a region around the stagnation point. Thus even with blunt cones, management of heat transfer rates and drag on bodies at hypersonic speeds continues to be an interesting research area. Various thermal protection systems have been proposed in the past, like heat sink cooling, ablation cooling and aerospikes. The ablative cooling system becomes extremely costly when reusability is the major concern. Also the shape change due to ablation can lead to issues with the vehicle control. The aerospikes themselves may become hot and ablate at hypersonic speeds. Hence an alternate form of cooling system is necessary for hypersonic flows, which is more feasible, cost effective and efficient than the conventional cooling systems. Injection of a mass of cold fluid into the boundary layer through the surface is one of the potential cooling techniques in the hypersonic flight corridors. These kinds of thermal protection systems are called mass transfer cooling systems. The injection of the mass may be through discrete slots or through a porous media. When the coolant is injected through a porous media over the entire surface, the coolant comes out as a continuous mass. Such a cooling system is also referred as “transpiration cooling system”. When the fluid is injected through discrete slots, the system is called as “film cooling system”. In either case, the coolant absorbs the incoming heat through its rise in enthalpy and thus modifies the boundary layer characteristics in such a way that the heat flow rate to the surface is less. Injection of a forward facing jet (opposite to the freestream direction) from the stagnation point of a blunt body can be used for mitigating both the aerodynamic drag and heat transfer rates at hypersonic Mach numbers. If the jet has enough momentum it can push the bow shock forward, resulting in reduced drag. This will also reduce heat transfer rate over most part of the body except around the jet re-attachment region. A reattachment shock impinging on the blunt body invariably increases the local heat flux. At lower momentum fluxes the forward facing jet cannot push the bow shock ahead of the blunt body and spreads easily over the boundary layer, resulting in reduced heat transfer rates. While the film cooling performance improves with mass flow rate of the jet, higher momentum flow rates can lead to a stronger reattachment leading to higher heat transfer rate at the reattachment zone. If we are able to reduce the momentum flux of the coolant for the same mass flow rate, the gas coming out can easily spread over the boundary layer and it is possible to improve the film cooling performance. In all the reported literature, the mass flow rate and the momentum flux are not varied independently. This means, if the mass flow rate is increased, there is a corresponding increase in the momentum flux. This is because the injection (from a particular orifice and for a particular coolant gas) is controlled only by the total pressure of injection and free stream conditions. The present investigation is mainly aimed at demonstrating the effect of reduction in momentum of the coolant (injected opposing a hypersonic freestream from the stagnation point of a blunt cone), keeping the mass flow rate the same, on the film cooling performance. This is achieved by splitting a single jet into a number of smaller jets of same injection area (for same injection total pressure and same free stream conditions). To the best of our knowledge there is no report on the use of forward facing micro-jet array for film cooling at hypersonic Mach numbers. In this backdrop the main objectives of the present study are: • To experimentally demonstrate the effect of splitting a single jet into an array of closely spaced smaller micro-jets of same effective area of injection (injected opposite to a hypersonic freestream from the stagnation zone), on the reduction in surface heat transfer rates on a large angle blunt cone. · Identifying various parameters that affect the flow phenomenon and doing a systematic investigation of the effect of the different parameters on the surface heat transfer rates and drag. Experimental investigations are carried out in the IISc hypersonic shock tunnel on the film cooling effectiveness. Coolant gas (nitrogen and helium) is injected opposing hypersonic freestream as a single jet (diameter 2 mm and 0.9 mm), and as an array of iv micro jets (diameter 300 micron each) of same effective area (corresponding to the respective single jet). The coolant gas is injected from the stagnation zone of a blunt cone model (58o apex angle and nose radius of 35 mm). Experiments are performed at a flow freestream Mach number of 5.9 at 0o angle of attack, with a stagnation enthalpy of 1.84 MJ/Kg, with and without injections. The ratios of the jet stagnation pressure to the pitot pressure (stagnation pressure ratio) used in the present study are 1.2 and 1.45. Surface convective heat transfer measurements using platinum thin film sensors, time resolved schlieren flow visualization and aerodynamic drag measurements using accelerometer force balance are used as flow diagnostics in the present study. The theoretical stagnation point heat transfer rate without injection for the given freestream conditions for the test model is 79 W/cm2 and the corresponding aerodynamic drag from Newtonian theory is 143 N. The measured drag value without injection (125 N) shows a reasonable match with theory. As the injection is from stagnation zone it is not possible to measure the surface heat transfer rates at the stagnation point. The sensors thus are placed from the nearest possible location from the stagnation point (from 16 mm from stagnation point on the surface). The sensors near the stagnation point measures a heat transfer rate of 65 W/cm2 on an average without any injection. Some of the important conclusions from the study are: • Up to 40% reduction in surface heat transfer rate has been measured near the stagnation point with the array of micro jets, nitrogen being the coolant, while the corresponding reduction was up to 30% for helium injection. Considering the single jet injection, near the stagnation point there is either no reduction in heat transfer rate or a slight increase up to 10%. · Far away from stagnation point the reduction in heat transfer with array of micro-jets is only slightly higher than corresponding single jet for the same pressure ratio. Thus the cooling performance of the array of closely spaced micro jets is better than the corresponding single jet almost over the entire surface. • The time resolved flow visualization studies show no major change in the shock standoff distance with the low momentum gas injection, indicating no major changes in other aerodynamic aspects such as drag. · The drag measurements also indicate that there is virtually no change in the overall aerodynamic drag with gas injection from the micro-orifice array. · The spreading of the jets injected from the closely spaced micro-orifice array over the surface is also seen in the visualization, indicating the absence of a region of strong reattachment. · The reduction in momentum flux of the injected mass due to the interaction between individual jets in the case of closely spaced micro-jet array appears to be the main reason for better performance when compared to a single jet. The thesis is organized in six chapters. The importance of film cooling at hypersonic speeds and the objectives of the investigation are concisely presented in Chapter 1. From the knowledge of the flow field with counter-flow injection obtained from the literature, the important variables governing the flow phenomena are organized as non-dimensional parameters using dimensional analysis in Chapter 2. The description of the shock tunnel facility, diagnostics and the test model used in the present study is given in Chapter 3. Chapter 4 describes the results of drag measurements and flow visualization studies. The heat transfer measurements and the observed trends in heat transfer rates with and without coolant injection are then discussed in detail in Chapter 5. Based on the obtained results the possible physical picture of the flow field is discussed in Chapter 6, followed by the important conclusions of the investigation.

Esta pesquisa foi realizada em um Instituto Federal de Educação, Ciência e Tecnologia e dedicou-se ao estudo de alguns conceitos de Física Quântica na formação de professores de Física, sob a perspectiva do referencial sociocultural, tendo o foco dirigido à complementaridade de segundo tipo, uma das teses da interpretação de Copenhagen, e ao emaranhamento quântico. O marco teóricometodológico adotado foi a teoria da mediação de Vygotsky e a filosofia translinguística de Bakhtin. Foram realizados três estudos qualitativos com o objetivo de investigar quais são os significados socialmente construídos sobre conceitos de Física Quântica por professores de Física em formação, sendo um estudo piloto e duas intervenções didáticas junto a uma disciplina de Física Moderna e Contemporânea em nível de graduação. As atividades de ensino foram conduzidas a partir de exposições teóricas e simulação computacional com o Interferômetro Virtual de Mach-Zehnder, orientada por roteiros exploratórios. A partir do estudo dos fenômenos da interferência e emaranhamento quânticos nesse dispositivo semiótico, buscou-se compreender em que medida as ações mediadas pelo uso do software como recurso didático atuaram no sentido de promover entre os professores uma construção conceitual colaborativa sobre esses conceitos da Física Quântica. A análise do discurso, fundamentada em conceitos bakhtinianos, possibilitou uma melhor compreensão sobre o processo de construção de conceitos culturalmente válidos acerca da interferência quântica, da complementaridade e do emaranhamento. No contexto explorado, verificamos que se estabeleceu o dilema da manutenção de visões antagônicas, o que pode ser evidenciado a partir dos modelos explicativos elaborados pelos estudantes. Para aqueles que atribuíram um caráter corpuscular aos fótons, os fenômenos intermediários permanecem como um conflito ainda não resolvido, enquanto para os demais a complementaridade onda-partícula passou a compor um nova classe de conceitos. A noção de não-localidade, necessária para compreender o emaranhamento quântico, não foi reconhecida pelos estudantes, evidenciando a forte presença de noções clássicas nos modelos explicativos utilizados na tentativa de obter uma explicação plausível para o fenômeno. / The research presented in this thesis was developed in a Federal Institute of Education, Science and Technology is directed to research about an approach of the some foundations of Quantum Physics in pre-service teachers’ training, based on the sociocultural perspective and this work focuses on the second kind of complementarity, one of the thesis of the Copenhagen interpretation, and the quantum entanglement. The theoretical and methodological framework adopted in this research is the Vygotsky’s theory of mediation and Bakhtin’s translinguistics philosophy. Three qualitative researches were performed in order to investigate which are the socially constructed meanings on QP foundations in the context of pre-service teachers’ training: one in an introductory course with physics teachers and two along a didactic intervention during a pre-service teachers’ training course on Modern and Contemporary Physics. The teaching activities were conducted mediated by theoretical lectures and computer simulation using the Virtual Mach- Zehnder Interferometer, conducted by the exploratory guide. From the study of interference phenomena and quantum entanglement in this semiotic tool, one tries to understand how the pupils actions are mediated by the software in the sense of promoting a collaborative conceptual construction among teachers about these foundations of QP. Discourse analysis grounded on Bakhtin’s concepts allowed us to evaluate the potentialities of the software and a better understanding of the process of conceptual construction that are culturally valid about quantum interference, complementarity and entanglement. In this context we perceive that was created the dilemma of maintaining competing visions, which can be evidenced from the explanatory models designed by the students. For the students that admitted a corpuscular character to photons so that intermediate phenomena remain as a unresolved cognitive conflict, while for others the wave - particle complementarity has became a new class of concepts. The non-locality notion, pre-requisite to understand the quantum entanglement, wasn’t learned by the students, demonstrating the strong presence of classical notions in explanatory models used to obtain a plausible explanation for the phenomenon.

Depuis plusieurs années, le volume de données échangé à travers le monde augmente sans cesse. Pour gérer cette large quantité d’information, des débits élevés de transmission de données sur de longues distances sont essentiels. Puisque les interconnections à base de cuivre ne peuvent pas suivre cette tendance, des systèmes de transmission optique rapides sont requis dans les centre de données. Dans ce contexte, la photonique sur silicium est considérée comme une solution pour obtenir des circuits photoniques intégrés à un coût réduit. Bien que cette technologie ait connu une croissance significative au cours de la dernière décennie, les transmetteurs actuels à haut débit de transmission sont principalement basés sur des sources laser externes. Par conséquent, l’objectif de ce travail de thèse était de concevoir et produire un transmetteur à haut débit de transmission de données pour la photonique sur silicium, doté d’une source laser intégrée.Ce transmetteur se compose d’un modulateur silicium de type Mach-Zehnder, co-intégré sur la même plaque avec un laser hybride III-V sur silicium à réseaux de Bragg distribués, dont la longueur d’onde d’émission peut être contrôlée électriquement autour de 1.3μm. La conception des différents éléments constituant à la fois le laser (coupleurs adiabatique entre le III-V et le silicium, miroirs de Bragg) et le modulateur (jonctions p-n, électrodes à ondes progressives) est détaillée, de même que leur fabrication. Pendant la caractérisation des transmetteurs, des taux de transmission de données jusqu’à 25Gb/s, pour des distances allant jusqu’à 10km ont été démontrés avec succès, avec la possibilité de contrôler la longueur d’onde jusqu’à 8.5nm. Par ailleurs, afin d’améliorer l’intégration de la source laser avec le circuit photonique sur silicium, une solution basée sur le dépôt à basse température (en-dessous de 400°C) d’une couche de silicium amorphe pendant la fabrication est aussi évaluée. Des tests sur une cavité laser à contre-réaction distribuée ont montré des performances au niveau de l’état de l’art (avec des puissances de sortie supérieures à 30mW), prouvant ainsi la viabilité de cette approche. / For several years, the volume of digital data exchanged across the world has increased relentlessly. To manage this large amount of information, high data transmission rates over long distances are essential. Since copper-based interconnections cannot follow this tendency, high-speed optical transmission systems are required in the data centers. In this context, silicon photonics is seen as a way to obtain fully integrated photonic circuits at an expected low cost. While this technology has experienced significant growth in the last decade, the high-speed transmitters demonstrated up to now are mostly based on external laser sources. Thus, the aim of this PhD thesis was to design and produce a high-speed silicon photonic transmitter with an integrated laser source.This transmitter is composed of a high-speed silicon Mach-Zehnder, co-integrated on the same wafer with a hybrid III-V on silicon distributed Bragg reflector laser, which emission wavelength can be electrically tuned in the 1.3μm wavelength region. The design of the various elements constituting both the laser (III-V to silicon adiabatic couplers, Bragg reflectors) and the modulator (p-n junctions, travelling-wave electrodes) is thoroughly detailed, as well as their fabrication. During the characterization of the transmitters, high-speed data transmission rates up to 25Gb/s, for distances up to 10km are successfully demonstrated, with the possibility to tune the operating wavelength up to 8.5nm. Additionally, in order to further improve the integration of the laser source with the silicon photonic circuit, a solution based on the low-temperature (below 400°C) deposition of an amorphous silicon layer during the fabrication process is also evaluated. Tests on a distributed feed-back laser structure have shown performances at the state-of-the-art level (with output powers above 30mW), thus establishing the viability of this approach.

Le contexte de cette étude est l’optimisation de la combustion turbulente prémélangée de syngaz pour la production propre d’énergie. Un brûleur CH4/air de type bec Bunsen avec forçage turbulent multi-échelles produit par un système de trois grilles, est simulé numériquement par différentes techniques de simulation des grandes échelles (SGE), et les résultats sont comparés à l’expérience. On a développé et appliqué une formulation bas-Mach du solveur Navier-Stokes basé sur différents schémas numériques, allant des différences finies centrées d’ordre 4 à des versions avancées des schémas WENO d’ordre 5. La méthodologie est évaluée sur une série de cas-tests classiques (flamme laminaire 1D prémélangée, turbulence homogène et isotrope en auto-amortissement), et sur des simulations 2D de la flamme turbulente prémélangée expérimentale. Les SGE implicites (ILES), i.e. sans aucune modélisation sous-maille, et explicites avec le modèle de flamme épaissie et un modèle de plissement sous-maille nouvellement élaboré (TFLES), sont appliquées à la simulation 3D du brûleur expérimental. Les résultats montrent que l’approche TFLES avec un schéma d’ordre élevé à faible dissipation numérique prédit correctement la longueur de la flamme et la densité de surface de flamme. La SGE implicite avec un schéma WENO avancé produit une flamme trop courte mais réaliste à condition que la taille de la maille soit de l’ordre de l’épaisseur de flamme laminaire. La représentation des interactions flamme/turbulence est néanmoins très différente entre TFLES et ILES. / The context of this study is the optimization of premixed turbulent combustion of syngas for clean energy production. A Bunsen-type CH4/air turbulent premixed burner with a multi-scale grid generator is simulated with different Large Eddy Simulation (LES) strategies and compared to experimental results. A low-Mach formulation of a compressible Navier-Stokes solver based on different numerical methods, ranging from 4th order central finite difference to 5th order advanced WENO schemes, is developed and applied. Classical test cases (1D laminar premixed flame, decaying HIT), and 2D simulations of the turbulent premixed flame are performed to assess the numerical methodology. Implicit LES (ILES), i.e. LES without any explicit subgrid modeling, and explicit LES with the Thickened Flame model and subgrid scale flame wrinkling modelling (TFLES) are applied to simulate numerically the 3D experimental burner. Results show that TFLES with a high-order low dissipation scheme predicts quite well the experimental flame length and flame surface density. ILES with advanced WENO schemes produces a slightly shorter although realistic flame provided the grid spacing is of order of the laminar flame thickness. The representation of flame/turbulence interactions in TFLES and ILES are however quite different.

Este trabalho descreve a utilização de um software livre educacional do interferômetro de Mach-Zehnder (IMZ), em português, como instrumento motivador, ilustrativo, de fácil manuseio e compreensão, para ajudar no ensino e aprendizagem de Física. Salientamos que este software educacional foi desenvolvido através de um projeto coordenado pelas professoras Fernanda Ostermann e Flávia Rezende, do Instituto de Física da Universidade Federal do Rio Grande do Sul (UFRGS) e da Universidade Federal do Rio de Janeiro (UFRJ) e foi utilizado como principal instrumento para introduzir conceitos fundamentais de física quântica em uma disciplina do curso Mestrado Profissional de Ensino de Física. No entanto, podemos dizer que esta foi a primeira vez que o IMZ foi aplicado a uma turma de professores não ligados profissionalmente à UFRGS. Em acréscimo ao software, foram elaborados e remodelados como produtos educacionais, textos de apoio e guias experimentais que poderão ser usados tanto por professores, como por alunos do Ensino Médio. Fenômenos ondulatórios foi o assunto explorado e um de seus subtemas, a interferência da luz, foi bastante enfatizada. Colocamos à disposição dos professores um material didático de fácil interpretação, podendo, também, ser utilizado com alunos do Ensino Médio. O desenvolvimento desse material tem caráter estratégico para que sirva de base a futuras transposições de temas da física quântica, em particular, o fenômeno da dualidade onda-partícula, para este nível de ensino. Este material de apoio e o software compreendem um curso de quarenta horas, para um grupo de seis professores da rede estadual, mais especificamente para os professores que lecionam Física, nas escolas que representam a 6ª Coordenadoria Regional de Educação (6ª CRE), com o apoio da mesma. O curso aconteceu em 2006, na Escola Estadual de Ensino Médio “Ernesto Alves de Oliveira”, em Santa Cruz do Sul, RS. Embasado na Teoria de Aprendizagem Significativa de Ausubel, o material servirá, também, como base ou conhecimento prévio para futuras investidas em outros temas relacionados à física quântica. O conteúdo da teoria ondulatória da luz, trabalhado sobre o aparato do interferômetro virtual de Mach-Zehnder proporcionou a interação entre o conhecimento novo (física quântica e dualidade ondapartícula, desenvolvida sobre o interferômetro virtual de Mach-Zehnder no regime quântico) e o prévio (teoria ondulatória da luz desenvolvida sobre o interferômetro virtual de Mach- Zehnder clássico), possibilitando uma aprendizagem significativa e dando sentido às novas informações. No decorrer do curso, ao analisarmos o comportamento e as atitudes dos professores, pudemos perceber que este assunto não é trabalhado no Ensino Médio, e que eles apresentam dificuldades em relação aos conceitos fundamentais da teoria. Entretanto, parte do grupo mostrou interesse em obter novos conhecimentos, pois em todos os encontros havia questionamentos relacionando novos conceitos com os pré-existentes. Enfim, o software gerou visível entusiasmo com as novas possibilidades de aulas “práticas”, com a aprendizagem dos novos conceitos e também a proposta de se avaliar com a utilização de mapas conceituais, estratégia desenvolvida por Novak. / In this work it is shown how the utilization of a free educational software can be useful as a motivating and illustrative tool to help the teaching and understanding of fundamental concepts on quantum mechanics. Besides being available also in Portuguese, the virtual Mach-Zehnder Interferometer (MZI) is easy to handle. The software has been developed under a project coordinated by Professor Ostermann (UFRGS) and Professor Rezende (UFRJ) and has been used as a main tool to introduce students from Mestrado Profissional em Ensino de Física to fundamental concepts on quantum physics. Here, it is reported the first time the software was used in an environment that is not university. Concepts of quantum physics were discussed in a 40 hours course given to a group of six secondary level school teachers in 2006. They were teachers working under the 6ª Coordenadoria Regional de Educação (6ª CRE). The course took place in Santa Cruz do Sul (RS) at Escola Estadual de Ensino Médio “Ernesto Alves de Oliveira”. In order to help the students with the software itself and physical concepts that could help the understanding of the simulations results, supporting materials like helping texts and experimental guides were prepared based on Ausubel framework. We were also concerned about an educational product that could also be helpful to secondary level school students. The texts are available in an easy language and straightforward physics. Although the number of students were relatively small, the group was representative in the sense it reproduces the reality of public secondary schools in Brazil. Physics is not, in general, taught by people that are graduated in Licenciatura em Física and the ones that are, are in general, not very well prepared. It was clear that no one in the group had enough confidence “to touch” subjects related to quantum physics in classes having the excuse this is a very difficult topic to overcome. Using optical physics as basis and the virtual MZI, we could see some enthusiasm when the students realize it is possible, for example, to discuss some concepts related to wave-particle duality without unreachable mathematics.

Esta pesquisa foi realizada em um Instituto Federal de Educação, Ciência e Tecnologia e dedicou-se ao estudo de alguns conceitos de Física Quântica na formação de professores de Física, sob a perspectiva do referencial sociocultural, tendo o foco dirigido à complementaridade de segundo tipo, uma das teses da interpretação de Copenhagen, e ao emaranhamento quântico. O marco teóricometodológico adotado foi a teoria da mediação de Vygotsky e a filosofia translinguística de Bakhtin. Foram realizados três estudos qualitativos com o objetivo de investigar quais são os significados socialmente construídos sobre conceitos de Física Quântica por professores de Física em formação, sendo um estudo piloto e duas intervenções didáticas junto a uma disciplina de Física Moderna e Contemporânea em nível de graduação. As atividades de ensino foram conduzidas a partir de exposições teóricas e simulação computacional com o Interferômetro Virtual de Mach-Zehnder, orientada por roteiros exploratórios. A partir do estudo dos fenômenos da interferência e emaranhamento quânticos nesse dispositivo semiótico, buscou-se compreender em que medida as ações mediadas pelo uso do software como recurso didático atuaram no sentido de promover entre os professores uma construção conceitual colaborativa sobre esses conceitos da Física Quântica. A análise do discurso, fundamentada em conceitos bakhtinianos, possibilitou uma melhor compreensão sobre o processo de construção de conceitos culturalmente válidos acerca da interferência quântica, da complementaridade e do emaranhamento. No contexto explorado, verificamos que se estabeleceu o dilema da manutenção de visões antagônicas, o que pode ser evidenciado a partir dos modelos explicativos elaborados pelos estudantes. Para aqueles que atribuíram um caráter corpuscular aos fótons, os fenômenos intermediários permanecem como um conflito ainda não resolvido, enquanto para os demais a complementaridade onda-partícula passou a compor um nova classe de conceitos. A noção de não-localidade, necessária para compreender o emaranhamento quântico, não foi reconhecida pelos estudantes, evidenciando a forte presença de noções clássicas nos modelos explicativos utilizados na tentativa de obter uma explicação plausível para o fenômeno. / The research presented in this thesis was developed in a Federal Institute of Education, Science and Technology is directed to research about an approach of the some foundations of Quantum Physics in pre-service teachers’ training, based on the sociocultural perspective and this work focuses on the second kind of complementarity, one of the thesis of the Copenhagen interpretation, and the quantum entanglement. The theoretical and methodological framework adopted in this research is the Vygotsky’s theory of mediation and Bakhtin’s translinguistics philosophy. Three qualitative researches were performed in order to investigate which are the socially constructed meanings on QP foundations in the context of pre-service teachers’ training: one in an introductory course with physics teachers and two along a didactic intervention during a pre-service teachers’ training course on Modern and Contemporary Physics. The teaching activities were conducted mediated by theoretical lectures and computer simulation using the Virtual Mach- Zehnder Interferometer, conducted by the exploratory guide. From the study of interference phenomena and quantum entanglement in this semiotic tool, one tries to understand how the pupils actions are mediated by the software in the sense of promoting a collaborative conceptual construction among teachers about these foundations of QP. Discourse analysis grounded on Bakhtin’s concepts allowed us to evaluate the potentialities of the software and a better understanding of the process of conceptual construction that are culturally valid about quantum interference, complementarity and entanglement. In this context we perceive that was created the dilemma of maintaining competing visions, which can be evidenced from the explanatory models designed by the students. For the students that admitted a corpuscular character to photons so that intermediate phenomena remain as a unresolved cognitive conflict, while for others the wave - particle complementarity has became a new class of concepts. The non-locality notion, pre-requisite to understand the quantum entanglement, wasn’t learned by the students, demonstrating the strong presence of classical notions in explanatory models used to obtain a plausible explanation for the phenomenon.

Este trabalho relata a produção, implementação e avaliação de um curso sobre física quântica destinado a alunos do Ensino Médio. A unidade didática foi inspirada nas propostas de Ostermann et al. (2009) e Pessoa Jr. (1997, 2003). Ela introduz a física quântica considerando a óptica ondulatória como um contexto para introduzir algumas analogias conceituais básicas para conceitos fundamentais da física quântica. O conceito central desta abordagem é a dualidade onda-partícula e o Interferômetro Virtual de Mach-Zehnder (IVMZ) é utilizado como sua ferramenta didática principal ou, em termos vygotskyanos, ferramenta de mediação. A proposta foi aplicada no formato de uma oficina extracurricular em uma escola privada de Porto Alegre no Brasil. Um dos professores de Física da escola se engajou e colaborou com este projeto. As aulas ocorreram entre os meses de Outubro e Novembro de 2013, em encontros semanais de uma hora. A perspectiva sociocultural de Vygotsky foi utilizada para embasar as aulas do curso. A translinguística de Bakhtin e os conceitos vygotskyanos foram utilizados para a análise das falas dos estudantes durante as atividades do curso. Nesta perspectiva analítica buscamos compreender como os estudantes elaboram estratégias discursivas para entender o conceito de dualidade onda-partícula, analisando a importância das interações com parceiros mais capazes (como professores), textos, simulações e outras ferramentas didáticas. Os resultados indicam que os estudantes desenvolveram algum domínio das ferramentas mediacionais necessárias para compreender a dualidade onda-partícula em um nível satisfatório. O Interferômetro Virtual de Mach-Zehnder, os roteiros exploratórios e os professores mostraram-se importantes para tornar mais efetivas as experiências de aprendizagem dos estudantes. / This dissertation reports the development, implementation and evaluation of a quantum physics course directed to high school students. The course was conceived inspired in proposals of Ostermann et al. (2009) and Pessoa Jr. (1997, 2003). It introduces quantum physics considering wave optics as a context to introduce some basic conceptual analogies to quantum fundamental concepts. The core concept of this approach is the wave-particle duality and the Virtual Mach-Zehnder Interferometer (VMZI) is used as its main didactical tool or, in vygotskyan terms, a mediational tool. The course was applied as an extracurricular workshop in a private school from Porto Alegre, Brazil. One of the school´s Physics teacher collaborated and engaged in this project. The classes took place between October and November 2013, in a set of one-hour weekly meetings. Vygotsky´s sociocultural perspective is adopted to ground the practices of the course. Both Bakhtin´s translinguistics and Vygotsky’s concepts were used to perform the analysis of students’ utterances along didactical activities at the classes. In this analytical framework, we try to understand how students elaborate discursive strategies to understand the concept of wave-particle duality, analyzing the importance of interaction with more experienced peers (like teachers), texts, simulation and other teaching tools. The results indicate that the students developed some mastery of mediational means needed to understand the wave-particle duality at a satisfactory level. The Virtual Mach-Zehnder Interferometer, the exploratory guides and the teachers were important to enhance the students’ learning experiences.