Este trabalho visa a determinação numérico-experimental de propriedades hidrodinâmicos em um cilindro de seção circular parcialmente submerso. A solução numérica do problema foi desenvolvida através do método dos painéis, o qual foi programado no pacote MATLAB®, sendo que o modelo do cilindro é excitado segundo os parâmetros de onda registrados a partir do ensaio de arrasto do cilindro, possibilitando a determinação da massa adicional e amortecimento hidrodinâmico. O desenvolvimento experimental foi efetivado através de ensaios em tanque de testes, com o uso de um carro de arrasto, tendo sido utilizado um sistema PIV (Particle Imagem Velocimetry) para mapear a não ocorrência da formação de vórtices na superfície submersa do cilindro. O cilindro foi fixado na base do carro, através de uma haste, na posição vertical, permanecendo parcialmente submerso nos ensaios de movimento oscilatório, com frequência e deslocamento longitudinal definidos. Nos ensaios, o conjunto de sensores no sistema detectou as variáveis de aceleração e carregamento na haste de sustentação do cilindro, deslocamento do carro e altura de onda, este último, realizado por dois wave probes simetricamente distanciados da posição inicial do cilindro. Os ensaios possibilitaram a obtenção da massa adicional e dos parâmetros necessários à solução numérica. O desenvolvimento da solução numérica hidrodinâmica via simulação em programa comercial foi realizado no pacote ANSYS® AQWATM, onde o cilindro foi modelado parcialmente submerso, sendo excitado pela frequência e velocidade de onda, os quais foram obtidos nos ensaios experimentais. Os resultados numéricos da programação e da simulação mostraram boa correspondência com os resultados experimentais. / This study involves the experimental and numerical determination of the hydrodynamic properties of a partially submerged cylinder with circular cross section. The numerical solution to the problem was developed using the panel method, which was programmed in the MATLAB® package, and the cylinder model was excited according to the wave parameters recorded during the cylinder drag test, enabling the determination of added mass and hydrodynamic damping. The experimental part of this study involved using a drag car in a test tank, with a PIV (Particle Image Velocimetry) system to map the non-occurrence of vortex formation on the submerged surface of the cylinder. The cylinder was attached vertically to the bottom of the car base by a rod, remaining partially submerged in the oscillatory motion tests, with defined frequency and longitudinal displacement. In the tests, the system’s sensor array detected the variables of acceleration and loading on the cylinder support rod, the car’s displacement and wave height, the latter measured by two wave probes placed at symmetrical distances from the cylinder’s initial position. The experimental tests made it possible to determine the added mass and the parameters required for the numerical solution. The development of the numerical solution of the hydrodynamic problem via simulation with commercial software was performed using the ANSYS® AQWATM package, in which the modeled cylinder was partially submerged and was excited by the wave frequency and velocity that were determined in the experimental tests. The numerical results of the programming and simulation showed a good correspondence with the experimental results.

Este trabalho visa a determinação numérico-experimental de propriedades hidrodinâmicos em um cilindro de seção circular parcialmente submerso. A solução numérica do problema foi desenvolvida através do método dos painéis, o qual foi programado no pacote MATLAB®, sendo que o modelo do cilindro é excitado segundo os parâmetros de onda registrados a partir do ensaio de arrasto do cilindro, possibilitando a determinação da massa adicional e amortecimento hidrodinâmico. O desenvolvimento experimental foi efetivado através de ensaios em tanque de testes, com o uso de um carro de arrasto, tendo sido utilizado um sistema PIV (Particle Imagem Velocimetry) para mapear a não ocorrência da formação de vórtices na superfície submersa do cilindro. O cilindro foi fixado na base do carro, através de uma haste, na posição vertical, permanecendo parcialmente submerso nos ensaios de movimento oscilatório, com frequência e deslocamento longitudinal definidos. Nos ensaios, o conjunto de sensores no sistema detectou as variáveis de aceleração e carregamento na haste de sustentação do cilindro, deslocamento do carro e altura de onda, este último, realizado por dois wave probes simetricamente distanciados da posição inicial do cilindro. Os ensaios possibilitaram a obtenção da massa adicional e dos parâmetros necessários à solução numérica. O desenvolvimento da solução numérica hidrodinâmica via simulação em programa comercial foi realizado no pacote ANSYS® AQWATM, onde o cilindro foi modelado parcialmente submerso, sendo excitado pela frequência e velocidade de onda, os quais foram obtidos nos ensaios experimentais. Os resultados numéricos da programação e da simulação mostraram boa correspondência com os resultados experimentais. / This study involves the experimental and numerical determination of the hydrodynamic properties of a partially submerged cylinder with circular cross section. The numerical solution to the problem was developed using the panel method, which was programmed in the MATLAB® package, and the cylinder model was excited according to the wave parameters recorded during the cylinder drag test, enabling the determination of added mass and hydrodynamic damping. The experimental part of this study involved using a drag car in a test tank, with a PIV (Particle Image Velocimetry) system to map the non-occurrence of vortex formation on the submerged surface of the cylinder. The cylinder was attached vertically to the bottom of the car base by a rod, remaining partially submerged in the oscillatory motion tests, with defined frequency and longitudinal displacement. In the tests, the system’s sensor array detected the variables of acceleration and loading on the cylinder support rod, the car’s displacement and wave height, the latter measured by two wave probes placed at symmetrical distances from the cylinder’s initial position. The experimental tests made it possible to determine the added mass and the parameters required for the numerical solution. The development of the numerical solution of the hydrodynamic problem via simulation with commercial software was performed using the ANSYS® AQWATM package, in which the modeled cylinder was partially submerged and was excited by the wave frequency and velocity that were determined in the experimental tests. The numerical results of the programming and simulation showed a good correspondence with the experimental results.

Este trabalho visa a determinação numérico-experimental de propriedades hidrodinâmicos em um cilindro de seção circular parcialmente submerso. A solução numérica do problema foi desenvolvida através do método dos painéis, o qual foi programado no pacote MATLAB®, sendo que o modelo do cilindro é excitado segundo os parâmetros de onda registrados a partir do ensaio de arrasto do cilindro, possibilitando a determinação da massa adicional e amortecimento hidrodinâmico. O desenvolvimento experimental foi efetivado através de ensaios em tanque de testes, com o uso de um carro de arrasto, tendo sido utilizado um sistema PIV (Particle Imagem Velocimetry) para mapear a não ocorrência da formação de vórtices na superfície submersa do cilindro. O cilindro foi fixado na base do carro, através de uma haste, na posição vertical, permanecendo parcialmente submerso nos ensaios de movimento oscilatório, com frequência e deslocamento longitudinal definidos. Nos ensaios, o conjunto de sensores no sistema detectou as variáveis de aceleração e carregamento na haste de sustentação do cilindro, deslocamento do carro e altura de onda, este último, realizado por dois wave probes simetricamente distanciados da posição inicial do cilindro. Os ensaios possibilitaram a obtenção da massa adicional e dos parâmetros necessários à solução numérica. O desenvolvimento da solução numérica hidrodinâmica via simulação em programa comercial foi realizado no pacote ANSYS® AQWATM, onde o cilindro foi modelado parcialmente submerso, sendo excitado pela frequência e velocidade de onda, os quais foram obtidos nos ensaios experimentais. Os resultados numéricos da programação e da simulação mostraram boa correspondência com os resultados experimentais. / This study involves the experimental and numerical determination of the hydrodynamic properties of a partially submerged cylinder with circular cross section. The numerical solution to the problem was developed using the panel method, which was programmed in the MATLAB® package, and the cylinder model was excited according to the wave parameters recorded during the cylinder drag test, enabling the determination of added mass and hydrodynamic damping. The experimental part of this study involved using a drag car in a test tank, with a PIV (Particle Image Velocimetry) system to map the non-occurrence of vortex formation on the submerged surface of the cylinder. The cylinder was attached vertically to the bottom of the car base by a rod, remaining partially submerged in the oscillatory motion tests, with defined frequency and longitudinal displacement. In the tests, the system’s sensor array detected the variables of acceleration and loading on the cylinder support rod, the car’s displacement and wave height, the latter measured by two wave probes placed at symmetrical distances from the cylinder’s initial position. The experimental tests made it possible to determine the added mass and the parameters required for the numerical solution. The development of the numerical solution of the hydrodynamic problem via simulation with commercial software was performed using the ANSYS® AQWATM package, in which the modeled cylinder was partially submerged and was excited by the wave frequency and velocity that were determined in the experimental tests. The numerical results of the programming and simulation showed a good correspondence with the experimental results.

La thèse porte sur la modélisation électromagnétique et la simulation de composites stratifiés plans (laminés), renforcés par des fibres organisées périodiquement. L'objectif est d'acquérir une bonne compréhension du comportement électromagnétique de telles structures, en première et étape de ce que pourrait ultérieurement être la production d’images mettant en évidence la localisation de zones éventuellement endommagées, et fournissant une certaine quantification de celles-ci. La thèse proprement dite se concentre donc sur la construction et l’évaluation de modèles de la diffraction électromagnétique par des composites multicouches tels que chaque couche est renforcée par des fibres disposées périodiquement.Est d’abord investiguée la diffraction par une plaque diélectrique (mono-couche) au sein de laquelle des fibres cylindriques de section circulaire de même rayon sont incorporées périodiquement, ces fibres ayant la même orientation de leurs axes et la même distance de centre à centre. Un cas bidimensionnel impliquant des ondes planes E ou H-polarisées, ainsi que des faisceaux gaussiens, normalement ou obliquement incidents, est d'abord pris en considération afin de mieux comprendre principes et philosophies des méthodes de choix, le couplage de mode et l'expansion multipolaire. Puis le travail est étendu, la diffraction de la plaque sous un éclairement tridimensionnel (conique) étant alors traitée en détail, ce qui montre aussi le potentiel de la méthodologie mise en œuvre si l’on souhaite obtenir la réponse électromagnétique de la structure à une source ponctuelle.Un composite multicouche, plus courant, mais plus complexe, qui est fait d’un empilement de plaques l'une sur l'autre, est alors étudié. Deux différentes espèces de composites sont ici prises en compte. Pour étudier la première, dont les fibres dans les différentes couches possèdent les mêmes orientations, des méthodes à base de matrices dites S ou dites T sont introduites, impliquant entre autre de s’intéresser à une résolution convenable du système linéaire produit selon le couplage de mode à la transition entre deux couches adjacentes. Une investigation de la deuxième espèce de composites suit alors, pour lequel les fibres au sein des différentes couches sont orientées dans des directions différentes quelconques, ce que permet une extension précautionneuse des approches précédentes. Une certaine attention est également portée au problème de l'homogénéisation des composites, de manière à lier les démarches à petite échelle telles que développées dans la thèse à celles à grande échelle souvent les seules prises en compte dans le contrôle non destructif et l’imagerie des composites stratifiés.De nombreux résultats de simulations numériques sont proposés et validés autant que possible par des résultats de référence de la littérature (notamment dans le cas de cristaux photoniques) et l'utilisation de solveurs « brute-force ». L'accent est aussi mis sur des cas particuliers de matériaux composites (ceux à base de fibres de verre et ceux à base de fibres de carbone) qui sont le plus souvent rencontrés dans les applications pratiques, avec des bandes de fréquences appropriées choisies en accord avec le comportement des fibres, principalement diélectrique ou principalement conducteur. / The contribution is about the electromagnetic modeling of fiber-reinforced periodically organized composite laminates. The final goal is to gain a good understanding of their electromagnetic behavior as well as to acquire images that should exhibit the location of possibly damaged zones, and provide some quantification of these zones. The thesis focuses on the scattering of well-organized periodic structures and building up an efficient full-wave computational model for multilayered composites, wherein each layer is reinforced by periodically arranged fibers, which is the first step for further investigation of the disorganized one.The work firstly considered the scattering problem of a slab in which infinite circular fibers, with the same radius, are periodically embedded with the same orientation of their axes and the same center-to-center distance. A 2-dimensional problem with normally and obliquely incident E- and H-polarized plane waves as well as Gaussian beams is firstly considered for understanding the principles and philosophies of the used mode-matching method and multipole expansion. Then the work is extended to the investigation if the scattering of the slab under illumination of a conically incident 3-dimensional electromagnetic wave, which shows the potential of the work for obtaining the response of the structure to a point source.A more practical but complicated multilayered composite, constructed by stacking up the slabs one over the other, is further investigated. Two different composites are taken into account. To study the first composite, with fibers in different layers having the same orientations, T-matrix- and S-matrix-based methods are introduced into the work for solving the linear system produced by mode-matching at the boundaries between two adjacent layers. Then, further investigation of the second kind of composite, wherein the fibers within different layers are orientated into different directions, is carried out by extending the approach properly.Some attention is also given to homogenization issues, so as to link small-scale approaches as developed in the thesis with large-scale ones as often considered in non-destructive testing of composite laminates.Extensive numerical simulations are proposed, validated whenever possible by reference results taken from the literature (notably in the case of photonic crystals) and the use of brute-force solvers. Emphasis is also on special cases of composites (glass-fiber- and graphite-fiber-based ones) as most often faced in practical applications, with appropriate frequency bands in harmony with the dielectric or conductive aspect of the fibers.

Moduladores espaciais de luz são elementos que fazem a modulação de uma frente de onda de modo a resultar em uma distribuição de luz desejada. Eles operam por difração, de acordo com o princípio de Huygens-Fresnel, e por este motivo são chamados Elementos Ópticos Difrativos (EODs). O foco deste trabalho é o estudo da modulação de frentes de onda, através da Teoria Escalar da Difração. O objetivo inicial foi o domínio do cálculo dos moduladores espaciais de luz, através da implementação do Algoritmo Iterativo da Transformada de Fourier. São calculados três EODs de fase: fase contínua, 4 níveis de fase e fase binária. Os resultados são avaliados através do cálculo da eficiência difrativa e da relação sinal-ruído. Para verificação do cálculo, hologramas binários foram fabricados usando filme fotográfico, de maneira simples e baixo custo. Algumas reconstruções simuladas e ópticas são apresentadas, demonstrando a viabilidade do uso do algoritmo na codificação de EODs. Em seguida, é feita a análise das frequências de ressonância de moduladores de ferroeletretos com canaleta, através de uma montagem experimental baseada no interferômetro de Michelson. Os ferroeletretos apresentam o efeito piezoelétrico e vêm sendo produzidos através de novas técnicas de fabricação. No campo da óptica tem-se o interesse em caracterizar ferroeletretos de modo a utilizá-los como possíveis moduladores de luz. São apresentados a montagem interferométrica em detalhes e o procedimento usado para medir as frequências de ressonância. Os resultados obtidos e as discussões demonstram a viabilidade do uso da montagem interferométrica proposta na caracterização de ferroeletretos. / Spatial light modulators perform the modulation of wavefront so that the desired light distribution is acquired. They work by diffraction, according to the Huygens-Fresnel principie, and for that they are called Diffractive Optical Elements (DOEs). The focus of this work is the study of light modulators through Scalar Diffraction Theory. The initial objective was to execute the calculation of spatial light modulators through the implementation of the so-called Iterative Fourier Transform AIgorithm. The calculation of three phase holograms is made: analog phase, 4 leveI phase and binary phase. The results are evaluated by calculating the diffraction efficiency and by signal to noise ratio. To verify the calculation, binary holograms were fabricated using photographic film in a simple and low cost way. Simulated and optical reconstructions are presented, showing the viability for the use of the algorithm in the coding of DOEs. Next, the resonance frequencies analysis in open tubular channels ferroelectrets is made through an experimental setup based in the Michelson interferometer. The ferroelectrets present the piezoelectric effect and are continuously produced through new techniques. In optics there is in interest in feroelectrets characterization in order to use them as spatial light modulators. The interferometric setup and the procedure used to measure the resonance frequencies are shown. The obtained results and discussion demonstrate the viability of the use of optical measurements in the characterization of ferroelectrets.

In this study nano-patterning was carried out using two different nano-optic devices namely- the NSOM and Fresnel zone plate. In the first study, NSOM was used to generate nano-patterns on selected semiconducting (Si and Ge) and metallic (Cr, Cu and Ag) targets under different laser pulse durations, laser energies and number of laser pulses. Based on the experimental results, femtosecond laser pulses, provided lower pattern generation thresholds on targets but higher damage thresholds to the NSOM probes at the wavelength (~400-410 nm) studied, compared with nanosecond laser pulses. Three different mechanisms were identified as the dominant processes for pattern generation under different conditions, namely nano-scale laser ablation, nano-scale thermal oxidation and nano-scale melting/recrystallization of the targets. Furthermore, the resulting nano-patterns also showed a significant dependence on the optical properties (i.e., absorption coefficient and surface reflectivity) of the target material. By comparing the obtained experimental results, it was concluded that the optical energy transport from the NSOM probe to the target dominates the pattern generation when femtosecond laser is applied to the NSOM system. When nanosecond laser is applied, both the thermal and optical energy transported from the NSOM probe to the targets attribute to the obtained morphology of nano-patterns on different targets under the experimental conditions studied. In the second study, a traditional Fresnel zone plate with a focus length of 3 micrometres was fabricated with a novel lift-off process in e-beam lithography. The fabrication process involved, using a HSQ/PMMA bi-layer in a negative tone lift-off process with a layer of conducting polyaniline for charge dissipation. HSQ was used as the high resolution negative resist for e-beam patterning and the PMMA under-layer was used to enable a HSQ lift-off process. The fabricated Fresnel zone plate was used to generate nano-patterns on a UV sensitive photoresist using nanosecond laser light with lamda~409nm. The smallest pattern sizes generated was close to the diffraction limit. Nano-pattern sizes generated on the photoresist were comparable with a numerically calculated intensity distribution at the focus spot of the designed Fresnel zone plate obtained from Scalar Diffraction Theory.

Moduladores espaciais de luz são elementos que fazem a modulação de uma frente de onda de modo a resultar em uma distribuição de luz desejada. Eles operam por difração, de acordo com o princípio de Huygens-Fresnel, e por este motivo são chamados Elementos Ópticos Difrativos (EODs). O foco deste trabalho é o estudo da modulação de frentes de onda, através da Teoria Escalar da Difração. O objetivo inicial foi o domínio do cálculo dos moduladores espaciais de luz, através da implementação do Algoritmo Iterativo da Transformada de Fourier. São calculados três EODs de fase: fase contínua, 4 níveis de fase e fase binária. Os resultados são avaliados através do cálculo da eficiência difrativa e da relação sinal-ruído. Para verificação do cálculo, hologramas binários foram fabricados usando filme fotográfico, de maneira simples e baixo custo. Algumas reconstruções simuladas e ópticas são apresentadas, demonstrando a viabilidade do uso do algoritmo na codificação de EODs. Em seguida, é feita a análise das frequências de ressonância de moduladores de ferroeletretos com canaleta, através de uma montagem experimental baseada no interferômetro de Michelson. Os ferroeletretos apresentam o efeito piezoelétrico e vêm sendo produzidos através de novas técnicas de fabricação. No campo da óptica tem-se o interesse em caracterizar ferroeletretos de modo a utilizá-los como possíveis moduladores de luz. São apresentados a montagem interferométrica em detalhes e o procedimento usado para medir as frequências de ressonância. Os resultados obtidos e as discussões demonstram a viabilidade do uso da montagem interferométrica proposta na caracterização de ferroeletretos. / Spatial light modulators perform the modulation of wavefront so that the desired light distribution is acquired. They work by diffraction, according to the Huygens-Fresnel principie, and for that they are called Diffractive Optical Elements (DOEs). The focus of this work is the study of light modulators through Scalar Diffraction Theory. The initial objective was to execute the calculation of spatial light modulators through the implementation of the so-called Iterative Fourier Transform AIgorithm. The calculation of three phase holograms is made: analog phase, 4 leveI phase and binary phase. The results are evaluated by calculating the diffraction efficiency and by signal to noise ratio. To verify the calculation, binary holograms were fabricated using photographic film in a simple and low cost way. Simulated and optical reconstructions are presented, showing the viability for the use of the algorithm in the coding of DOEs. Next, the resonance frequencies analysis in open tubular channels ferroelectrets is made through an experimental setup based in the Michelson interferometer. The ferroelectrets present the piezoelectric effect and are continuously produced through new techniques. In optics there is in interest in feroelectrets characterization in order to use them as spatial light modulators. The interferometric setup and the procedure used to measure the resonance frequencies are shown. The obtained results and discussion demonstrate the viability of the use of optical measurements in the characterization of ferroelectrets.

A main challenge in the field of special effects is to create special effects in real time in a way that the user can preview the effect before taking the actual picture or movie sequence. There are many techniques currently used to create computer-simulated special effects, however current techniques in computer graphics do not provide the option for the creation of real-time texture synthesis. Thus, while computer graphics is a powerful tool in the field of special effects, it is neither portable nor does it provide work in real-time capabilities. Real-time special effects may, however, be created optically. Such approach will provide not only real-time image processing at the speed of light but also a preview option allowing the user or the artist to preview the effect on various parts of the object in order to optimize the outcome. The work presented in this dissertation was inspired by the idea of optically created special effects, such as painterly effects, encoded in images captured by photographic or motion picture cameras. As part of the presented work, compact relay optics was assessed, developed, and a working prototype was built. It was concluded that even though compact relay optics can be achieved, further push for compactness and cost-effectiveness was impossible in the paradigm of bulk macro-optics systems. Thus, a paradigm for imaging with multi-aperture micro-optics was proposed and demonstrated for the first time, which constitutes one of the key contributions of this work. This new paradigm was further extended to the most general case of magnifying multi-aperture micro-optical systems. Such paradigm allows an extreme reduction in size of the imaging optics by a factor of about 10 and a reduction in weight by a factor of about 500. Furthermore, an experimental quantification of the feasibility of optically created special effects was completed, and consequently raytracing software was developed, which was later commercialized by SmARTLens(TM). While the art forms created via raytracing were powerful, they did not predict all effects acquired experimentally. Thus, finally, as key contribution of this work, the principles of scalar diffraction theory were applied to optical imaging of extended objects under quasi-monochromatic incoherent illumination in order to provide a path to more accurately model the proposed optical imaging process for special effects obtained in the hardware. The existing theoretical framework was generalized to non-paraxial in- and out-of-focus imaging and results were obtained to verify the generalized framework. In the generalized non-paraxial framework, even the most complex linear systems, without any assumptions for shift invariance, can be modeled and analyzed.

Investigations of soft matter using ultrashort high intensity pulses have been made possible through the advent of X-ray free-electrons lasers. The last decade has seen the development of a new type of protein crystallography where femtosecond dynamics can be studied, and single particle imaging with atomic resolution is on the horizon. The pulses are so intense that any sample quickly turns into a plasma. This thesis studies the ultrafast transition from soft matter to warm dense matter, and the implications for structural determination of proteins.                    We use non-thermal plasma simulations to predict ultrafast structural and electron dynamics. Changes in atomic form factors due to the electronic state, and displacement as a function of temperature, are used to predict Bragg signal intensity in protein nanocrystals. The damage processes started by the pulse will gate the diffracted signal within the pulse duration, suggesting that long pulses are useful to study protein structure. This illustrates diffraction-before-destruction in crystallography. The effect from a varying temporal photon distribution within a pulse is also investigated. A well-defined initial front determines the quality of the diffracted signal. At lower intensities, the temporal shape of the X-ray pulse will affect the overall signal strength; at high intensities the signal level will be strongly dependent on the resolution. Water is routinely used to deliver biological samples into the X-ray beam. Structural dynamics in water exposed to intense X-rays were investigated with simulations and experiments. Using pulses of different duration, we found that non-thermal heating will affect the water structure on a time scale longer than 25 fs but shorter than 75 fs. Modeling suggests that a loss of long-range coordination of the solvation shells accounts for the observed decrease in scattering signal. The feasibility of using X-ray emission from plasma as an indicator for hits in serial diffraction experiments is studied. Specific line emission from sulfur at high X-ray energies is suitable for distinguishing spectral features from proteins, compared to emission from delivery liquids. We find that plasma emission continues long after the femtosecond pulse has ended, suggesting that spectrum-during-destruction could reveal information complementary to diffraction.

Le contexte d’étude est celui de la Compatibilité ÉlectroMagnétique (CEM). L’objectif de la CEM est, comme son nom l’indique, d’assurer la compatibilité entre une source de perturbation électromagnétique et un système électronique victime. Or, la prédiction de ces niveaux de perturbation ne peut pas s’effectuer à l’aide d’un simple calcul analytique, en raison de la géométrie qui est généralement complexe pour le système que l’on étudie, tel que le champ à l’intérieur d’un cockpit d’avion par exemple. En conséquence, nous sommes contraints d’employer des méthodes numériques, dans le but de prédire ce niveau de couplage entre les sources et les victimes. Parmi les nombreuses méthodes numériques existantes à ce jour, les méthodes Multi-Domaines (MD) sont très prisées. En effet, elles offrent la liberté aux utilisateurs de choisir la méthode numérique la plus adaptée, en fonction de la zone géométrique à calculer. Au sein de ces méthodes MD, la « Domain Decomposition Method » (DDM) présente l’avantage supplémentaire de découpler chacun de ces domaines. En conséquence, la DDM est particulièrement intéressante, vis-à-vis des méthodes concurrentes, en particulier sur l’aspect du coût numérique. Pour preuve, l’ONERA continue de développer cette méthode qui ne cesse de montrer son efficacité depuis plusieurs années, notamment pour le domaine des Surfaces Équivalentes Radar (SER) et des antennes. L’objectif de l’étude est de tirer profit des avantages de cette méthode pour des problématiques de CEM. Jusqu’à maintenant, de nombreuses applications de CEM, traitées par le code DDM, fournissaient des résultats fortement bruités. Même pour des problématiques électromagnétiques très simples, des problèmes subsistaient, sans explication convaincante. Ceci justifie cette étude. Le but de cette thèse est de pouvoir appliquer ce formalisme DDM à des problématiques de CEM. Dans cette optique, nous avons été amenés à redéfinir un certain nombre de conventions, qui interviennent au sein de la DDM. Par ailleurs, nous avons développé un modèle spécifique pour les ouvertures, qui sont des voies de couplage privilégiées par les ondes, à l’intérieur des cavités que représentent les blindages. Comme les ouvertures sont, en pratique, de petites dimensions devant la longueur d’onde, on s’est intéressé à un modèle quasi-statique. Nous proposons alors un modèle, qui a été implémenté, puis validé. Suite à ce modèle, nous avons développé une méthode originale, basée sur un calcul en deux étapes, permettant de ne plus discrétiser le support des ouvertures dans les calculs 3D. / The context of the study is the ElectroMagnetic Compatibility (EMC). Principal aim of the EMC is to ensure the compatibility between an electromagnetic perturbance source and an electronic device victim. Unfortunately, the perturbation levels prediction can not be made using an analytic formula, because the geometry which is generally complex for the interesting system, for example the field inside an aircraft’s cockpit. Therefore, we are contrained to use numerical methods, to be able to evaluate this coupling level between sources and victims. Among several existing numerical methods, Multi-Domains (MD) methods are very interesting. They offer to users the freedom to choose the most powerfull numerical method, in terms of the geometrical zone evaluated. With the MD methods, « Domain Decomposition Method » (DDM) has the avantage of decouplingeach of theses areas. Therefore, DDM is very interesting, compared to other methods, in particular on the numerical cost. ONERA keeps on developing this method, which has not stop showing his efficiency since several years, in particular in Radar Cross Section (RCS) and antennas. The objective of this study is to take the benefits of this method for EMC problems. Up to now, several EMC applications treated by the DDM code provided results strongly noisy. Even for with very simple electromagnetic cases, some problems remained without convincing explanations. This justifies this study. The aim of this thesis is to can be able to apply DDM formalism to EMC problems. Then, we have been induced to redefine a number of conventions which are involved in the DDM. Otherwise, we have developed a specific model for the apertures which are privilegied tracts of the coupling by the penetration of waves inside cavities (shieldings). As the apertures have in practice smaller dimensions compared to the wavelength, we have been interested to a quasistatic model which was developped, implemented and validated. Following this model, we have developed an original method, based on a two step calculation, able to do not discretize the apertures support in 3D computations.