O formato do perfil de velocidades do vento varia de acordo com as características locais da superfície terrestre e de rugosidade do terreno, parâmetros que definem o perfil da Camada-Limite Atmosférica (CLA). As características do escoamento do ar atmosférico sobre e ao redor de acidentes geográficos, tais como morros e colinas, são de grande interesse para aplicações relacionadas à Engenharia de Turbinas e Parques Eólicos. No topo de morros, ocorre a aceleração do vento, fenômeno que pode representar um fator decisivo para a instalação de aerogeradores. Este trabalho dedica-se ao estudo do comportamento da CLA como função da inclinação e rugosidade superficial da elevação, fazendo uso da Dinâmica de Fluidos Computacional (CFD) para construir perfis de velocidade do vento e de intensidade de turbulência. O problema de fechamento das Equações Médias de Reynolds (RANS) é contornado com o uso do modelo de turbulência k-ω SST; os resultados numéricos obtidos são comparados com dados experimentais medidos em túnel de vento sobre modelos em escala dos morros. São testados oito modelos de morros com declives que variam de 25° a 64° para dois tipos de categorias de terreno, em 2D e 3D, e são aplicados dois códigos analíticos para representar o perfil de velocidades de entrada. Resultados numéricos para os perfis de velocidade apresentam diferença inferior a 4% em relação aos respectivos dados obtidos experimentalmente. Os perfis de intensidade de turbulência apresentam diferença máxima na casa dos 7% em comparação aos dados experimentais, o que é explicado pelo fato de que não é possível inserir o perfil de entrada de intensidade de turbulência nas simulações numéricas. Em alternativa, foi usado um valor constante resultado da média dos valores dos perfis usados no túnel de vento. Os modelos de morro em 3D apresentam maior concordância nos resultados de velocidade que os modelos em 2D e que ademais quanto maior é a inclinação do morro maior é a concordância com as medições experimentais. / The shape of the wind velocity profile changes according to local features of terrain shape and roughness, which are parameters responsible for defining the Atmospheric Boundary Layer (ABL) profile. Air flow characteristics over and around landforms, such as hills, are of considerable importance for applications related to Wind Farm and Turbine Engineering. The air flow is accelerated on top of hills, which can represent a decisive factor for Wind Turbine placement choices. The present work focuses on the study of ABL behavior as a function of slope and surface roughness of hill-shaped landforms, using the Computational Fluid Dynamics (CFD) to build wind velocity and turbulent intensity profiles. Reynolds-Averaged Navier-Stokes (RANS) equations are closed using the SST k-ω turbulence model; numerical results are compared to experimental data measured in wind tunnel over scale models of the hills under consideration. Eight hill models with slopes varying from 25° to 64° were tested for two types of terrain categories in 2D and 3D, and two analytical codes are used to represent the inlet velocity profiles. Numerical results for the velocity profiles show differences under 4% when compared to their respective experimental data. Turbulent intensity profiles show maximum differences around 7% when compared to experimental data, this can be explained by not being possible to insert inlet turbulent intensity profiles in the simulations. Alternatively, constant values based on the averages of the turbulent intensity at the wind tunnel inlet were used. The 3D models present greater concordance in the speed results than the 2D models and that in addition the greater the slope of the hill, the greater the agreement with the experimental measurements.

Uma importante estratégia de projeto para melhorar o desempenho térmico das edificações em climas quentes e úmidos é a adoção conjunta da ventilação natural e de dispositivos de sombreamento. Contudo, quando a ventilação natural é ocasionada pela ação dos ventos nas edificações, as pressões do vento nas envoltórias da edificação são alteradas com a presença de elementos externos próximos que mudam as características do fluxo incidente. Deste modo, o presente trabalho tem como objetivo avaliar os impactos na ventilação natural, e nas temperaturas internas do ar e/ou no conforto térmico de uma habitação térrea em um clima quente e úmido, a partir do uso de diferentes dispositivos de sombreamento externos e muro. Para isso, foram realizadas simulações computacionais no programa EnergyPlus através do módulo AirflowNetwork. Foram realizados ensaios em túnel de vento de Camada Limite Atmosférica (CLA) para a obtenção dos coeficientes de pressão (Cps). Os resultados apontaram impactos específicos a cada elemento estudado, no entanto o fenômeno mais frequente nos casos com dispositivos de sombreamento foi a redução dos efeitos de sobrepressão e sucção. Quanto aos seus impactos nas renovações de ar, estes provocaram uma diminuição do fluxo de ar e, consequentemente, o aumento da temperatura no período predominantemente noturno. Entretanto, foi observado um maior impacto na atenuação das temperaturas internas nos períodos diurnos, que prevaleceu sobre o aumento nos períodos de ventilação. Destacou-se, dentre os dispositivos de sombreamento estudados, as proteções tipo veneziana por proporcionarem um melhor desempenho térmico. Já os muros, dentre todos os elementos estudados, foram os que tiveram maior impacto nos Cps. Tal fenômeno significou a diminuição da taxa de renovação de ar dentre 50 e 75%. O impacto mais sobressalente nas temperaturas internas nestes casos foi o aumento destas no período noturno, limitando o potencial da ventilação natural para a remoção de calor da edificação / An important design strategy for improving the thermal performance of buildings in hot and humid climates is the adoption of natural ventilation strategies and shading devices combined. However, when natural ventilation is wind-driven, the wind pressures on the building envelope are altered by the presence of nearby external elements that change the incident flows characteristics. Thus, the present work aims to evaluate the impacts on natural ventilation, and the internal air temperatures and/or the thermal comfort of a single ground floor low-cost house in a hot and humid climate, considering the use of different external shading devices and walls. For such, computational simulations were performed in the EnergyPlus program using the AirflowNetwork module. Atmospheric Limit Wind (CLA) wind tunnel tests were performed to obtain pressure coefficients (Cps). The results indicated specific impacts to each element studied, however the most frequent phenomenon in cases with shading devices was the reduction of the effects of overpressure and suction. As for their impacts on air changes rate, they caused a decrease in airflow and, consequently, an increase in temperature predominantly in the nocturnal period. However, a greater impact was observed in the attenuation of internal temperatures in the daytime periods, which prevailed over the increase in ventilation periods., Among the shading devices studied, venetian type protections for providing better thermal performance were highlighted. Among all the elements studied, the walls had the greatest impact on the Cps. This phenomenon meant the reduction of the air changes rate between 50 and 75%. The most significant impact on internal temperatures in these cases was the their increase at night, limiting the potential of natural ventilation to the removal of heat from the building.

La ventilation naturelle est une stratégie passive qui permet l'échange naturel d'air entre le bâtiment et l'environnement extérieur. Elle assure une bonne qualité de l'air intérieur, améliore le confort thermique et elle réduit les besoins énergétiques, les émissions de gaz à effet de serre et les symptômes liés au syndrome du bâtiment malsain. Bien que les avantages et les bénéfices de la ventilation naturelle soient multiples, son usage est rare dans l'architecture contemporaine. Bien sûr, il existe des limites à sa mise en œuvre dans certains bâtiments, comme la mauvaise qualité de l'air extérieur, mais ces problèmes ne justifient pas une utilisation si peu répandue. La cause de sa faible diffusion est principalement liée à la difficulté de la conception plutôt que aux facteurs physiques liés à l'environnement. La thèse vise à fournir différents outils pour comprendre la dynamique des fluides dans les bâtiments et développer des techniques et des méthodes pour aider la conception des bâtiments ventilés naturellement. L'approche adoptée dans la thèse est modélisée selon les besoins du concepteur qui peut choisir d'utiliser différents types de supports tels que: utiliser des outils graphiques ou des modélisations numériques, s'inspirer de l'architecture contemporaine et répéter les solutions technologiques existantes, utiliser des outils de modélisation physique, s'inspirer du passé ou du monde naturel. Ici plusieurs aspects de la ventilation naturelle sont traités en apportant à chacun une contribution innovante afin de créer des outils d'aide pour différents phases de la conception : Les objectifs de la thèse sont de créer des outils innovants qui simplifient la conception à des niveaux différents. Nous avons créé donc, des outils et des modèles graphiques simplifiés pour choisir la forme du bâtiment et son orientation, des lignes directrices pour le dimensionnement des dispositifs de ventilation (cheminées de toit), des méthodes expérimentales simplifiées associées à des codes de lecture des écoulements d'air. Nous avons également élargit le panorama culturel et historiques et nous avons créé des indications morphologiques dérivant de l'analyse de l'architecture biomimétique. Grâce à une analyse CFD paramétrique, des outils graphiques sont générés pour évaluer, de manière comparative, les performances de ventilation d'une famille morphologique de bâtiments et choisir la forme du bâtiment, son orientation et la position des ouvertures. Nous créons des lignes directrices pour la conception et le pré-dimensionnement des dispositifs de ventilation. Les règles sont déterminées par une analyse comparative de neuf projets de bâtiments contemporains ventilés naturellement dans lesquels le dispositif de ventilation est présent. Une soufflerie est conçue et réalisée pour simplifier les visualisations des écoulements d'air autour des modèles de bâtiments et nous proposons une méthode pour réaliser des expérimentations de support à la conception. Le système de refroidissement géothermique d'une ancienne villa à Costozza (Vicence, Italie) est étudié. Cette section élargit la connaissance du patrimoine architectural italien et souligne l'importance de redécouvrir des solutions technologiques bioclimatiques existantes, toujours en fonction. On analyse une structure animale: le nid d'un insecte. Il s'agit d'un archétype bioclimatique qu'il peut être utilisé dans l'architecture en tant que technologie biomimétique / Natural ventilation is a passive ventilation strategy of confined spaces that consists of natural air exchange between the building and the outdoor environment. Natural ventilation ensures a good indoor air quality, it improves the thermal comfort and it reduces the greenhouses gases emission, the energy demand and the symptoms associated with the Sick Building Syndrome. Although the advantages and benefits of natural ventilation are multiple, its application is rare to contemporary architecture. By the way, there are some limits to its implementation, such as the bad quality of outdoor air, but that does not justify a so limited design of naturally ventilated buildings. The cause of its rare diffusion is primarily the difficulty of design rather than the factors related to the environment. The thesis intends to provide multiple tools for understanding the fluid dynamics in buildings and to develop techniques and methods to support the design of naturally ventilated buildings. The approach adopted in the thesis is modeled according to the needs of the designer. In fact, a designer can choose to use different types of support tools such as: use of graphic tools or numerical models, inspiration to contemporary architecture to provide the existing technology solutions, use of physical modeling tools, inspiration to the past or to the nature. Often, the design is a global process and does not need a single tool but the designer uses more than one. Here, several aspects of natural ventilation are dealt with, trying to make an innovative contribution to each of these themes, in particular : Through a parametric CFD analysis, graphical tools are generated to evaluate, adopting a comparative approach, the ventilative performance of a morphological family of buildings and to choose the shape of the building, its orientation and the position of the openings. Guidelines are set for the design and pre-dimensioning of ventilation devices. The rules are determined by a comparative analysis of nine contemporary ventilation projects in which the ventilation device is present. An optimized wind tunnel is created to simplify airflow visualizations around building models. We provide also a method to make simplified experimentations, an aiding-design tool, and a code that allows to understand the views with the smoke. We study the geothermal cooling system of an ancient villa in Costozza (Vicenza, Italy). This section extends the knowledge of the Italian architectural heritage and highlights the importance of rediscovering existing bioclimatic technology solutions, still in operation. An animal structure is analysed: the bug of an insect. This is a bioclimatic archetype and therefore it can be applied to architecture as a biomimetic technology

Submitted by MARCELO FRANCISCO MAESTÁ null (mfmaesta@gmail.com) on 2017-02-22T00:41:17Z No. of bitstreams: 1 Tese MArcelo Francisco Maesta.pdf: 11803249 bytes, checksum: c99c02808167e733ec292281a2b8c183 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-24T18:06:13Z (GMT) No. of bitstreams: 1 maestra_mf_dr_ilha.pdf: 11803249 bytes, checksum: c99c02808167e733ec292281a2b8c183 (MD5) / Made available in DSpace on 2017-02-24T18:06:13Z (GMT). No. of bitstreams: 1 maestra_mf_dr_ilha.pdf: 11803249 bytes, checksum: c99c02808167e733ec292281a2b8c183 (MD5) Previous issue date: 2016-12-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A busca por aeronaves capazes de modificar sua geometria melhorando suas características aerodinâmicas incentivou diversos autores a sugerirem modelos de asas adaptativas. Tais modelos utilizam atuadores leves de modo a substituir os atuadores clássicos convencionais sem, no entanto, comprometer a e ciência de voo da aeronave. Dentre os materiais utilizados para isto se destacam as ligas de memória de forma (Ni-Ti), que são capazes de converter energia térmica em energia mecânica e, uma vez deformadas, podem retornar a sua condição original de forma através de seu aquecimento. Neste contexto, o presente trabalho objetiva controlar a posição angular de um aerofólio utilizando para isto um par de os de liga de memória de forma. No modelo de asa proposto, deseja-se estabelecer uma forma para o per l aerodinâmico a partir da determinação de um ângulo entre duas seções da asa. Este ângulo é atingido pelo efeito de memória de forma da liga através da passagem de uma corrente elétrica. A função da corrente elétrica é alterar a temperatura dos atuadores através do efeito Joule, modificando a forma da liga. Devido à presença de efeitos não-lineares, principalmente no modelo matemático da liga, propõe-se a aplicação de controladores não-lineares do tipo liga-desliga. / The search for aircraft capable of modifying its geometry improving its aerodynamic characteristics, encouraged several authors to suggest models of adaptive wings. These models use lightweight actuators to replace conventional classic actuators without, however, compromise aircraft flight efficiency. Shape Memory Alloys (SMA) can be used efficiently for this application. These materials are capable of converting thermal energy into mechanical energy and a deformed time, can return to its original condition so through its heating. The current work aims to control the angular position of an airfoil using a couple of alloy wires of shape memory. In the proposed wing model, it is desired to establish a way for the aerodynamic pro le of the determination of an angle between two sections of the wing. This angle is attained by the alloy shape memory effect by passing an electric current. The function of the electric current is to change the temperature of the actuators through the Joule effect, modifying the shape of the shape memory alloy. Due to the presence of non-linear effects, especially in the mathematical model of the alloy, it proposes the application of nonlinear controllers type on-of

Cette étude vise à caractériser en soufflerie les mécanismes aérodynamiques à l’origine de la génération puis la transmission des fluctuations de bruit dans un modèle d’habitacle automobile. Le banc d’essai conçu en soufflerie anéchoïque consiste en un écoulement dont la vitesse incidente est modulée par un volet mobile, et qui par interaction avec une marche montante rayonne un bruit aéroacoustique transmis à travers une vitre dans un caisson anéchoïque. L’approche retenue consiste, pendant le temps de maniement du volet, à mesurer et relier le champ de vitesse externe mesuré à l’aide de la technique de vélocimétrie laser par images de particules (TR-PIV échantillonnée à 20 kHz) à la pression pariétale d’une part, puis au champ acoustique interne obtenu par transmission d’autre part. Des outils de corrélation spatio-temporelle sont alors utilisés pour mettre en évidence les zones de l’écoulement les plus corrélées avec les fluctuations d’énergie de la pression pariétale et celles du niveau de bruit intérieur. La fluctuation du chargement aérodynamique de la vitre sous la bulle de recirculation est logiquement liée à l’activité instationnaire de cette dernière, puis plus en aval, au lâcher tourbillonnaire. Quant au bruit transmis dans le modèle d’habitacle, il semble principalement lié aux fluctuations de vitesse dans la couche de cisaillement. Enfin, une procédure spécifique a permis d’évaluer le caractère quasi-stationnaire des variations temporelles des quantités fluctuantes ainsi que la réponse acoustique de la vitre. / This study aims at characterizing in a wind tunnel the aerodynamic mechanisms contributing to the generation and transmission of the noise fluctuations into a car interior model. The test bench designed in anechoic wind tunnel consists of a flow whose incoming flow velocity is modulated by a mobile flap, and which by interaction with a forward-facing step radiates an aeroacoustic noise transmitted through a glass into an anechoic box. The adopted approach consists, during the flap handling time, in measuring and connecting the external velocity field measured using the Time-Resolved laser Particle Image Velocimetry technique (TR-PIV at sampling frequency 20 kHz) to the wall pressure on the one hand, and then to the internal acoustic field obtained by transmission on the other hand. Spatio-temporal correlation tools are then used to highlight the flow areas that are the most correlated with the energy fluctuations of the wall pressure and with those of the internal noise level. The fluctuation of the aerodynamic loading of the window under the recirculation bubble is logically related to the unsteady activity of the latter, then further downstream to the vortex stream. As for the noise transmitted into the cabin model, it seems mainly related to the speed fluctuations in the shear layer. Finally, a specific procedure allows to evaluate the quasi-steady nature of the temporal variations of the fluctuating quantities, as well as the acoustic response of the window.

Afin de bénéficier de vents importants, un nombre croissant d'éoliennes est installé en terrain complexe. Cependant, un terrain complexe accroit la complexité de l'écoulement et donc la prédiction du potentiel éolien. Dans ce travail, le vent en terrain complexe est simulé en soufflerie. L'objectif est d'étudier la capacité de la modélisation en soufflerie.La partie basse de l'atmosphère, appelée couche limite atmosphérique, est le siège d'important gradients de vitesse et de turbulence. Dans la soufflerie, ils sont reproduits grâce à des obstacles placés dans la section d'essai. Leurs tailles varient en fonction du type de terrain à modéliser. Cette approche expérimentale est validée par des données terrain. La reproduction des conditions atmosphériques est le paramètre crucial pour une bonne modélisation.Pour évaluer le vent en terrain complexe, le choix de la zone à reproduire autour du site d'intérêt est une question centrale : elle doit tenir compte de l'effet des reliefs environnants mais doit être assez réduite pour préserver un facteur d'échelle raisonnable dans la soufflerie. Une série d'études sur des collines simplifiées est ainsi réalisé afin de déterminer l'étendue spatiale du sillage en aval d'un relief simplifié afin de rationaliser le choix de la zone d'étude.Deux cas réels sont ensuite traités, l'ile de Bolund au Danemark et la montagne Alaiz en Espagne. Les résultats sont bons pour l'estimation de la vitesse du vent, entre 5 et 10 % mais la modélisation de la turbulence est plus difficile, des écarts jusqu'à 100 % sont enregistrés comparés aux données terrain. / To benefit from strong winds, an increasing number of wind turbines are placed in complex terrains. But complex terrains means complex flows and difficult wind resource assessment. This study proposed to use wind tunnel modelling to evaluate the wind in a complex topography. The goal of this study is to evaluate the possibilities of wind resources assessment by wind tunnel modelling and to quantify the important modelling parameters. The lower part of the atmosphere, the atmospheric boundary layer (ABL) is defined by a velocity and a turbulence gradient. The ABL is reproduced in the wind tunnel by placing obstacles and roughness elements of different size representative to the type of terrain desired. The flow produced in the wind tunnel is validated against field data and a wise choice of the obstacles is discussed to reproduce the desired wind profile. The right reproduction of the inflow conditions is found to be the most important parameter to reproduce. The choice of the area to reproduce around a site in usually difficult to make in order to keep a low scaling factor and to account for the surrounding topography. A series of tests on simplified hills helps the experimentalist in this choice by enlightening the longitudinal and vertical extension of the wake downstream different hills shapes. Finally, two complex topographies are studied in two wind tunnels, the Bolund hill in Denmark and the Alaiz mountain in Spain. The results are giving good results, 5 to 10 %, for predicting the wind speed but more scatter is observed for the modelling of the turbulence, up to 100 %. The laboratory simulation of atmospheric flows proves to be a demanding but reliable tool for the prediction of the mean wind speed in complex terrain.

L’érosion éolienne des matières granulaires (minerais, charbons,. . . ) est un des facteurs influençant grandement la qualité de l’air dans l’environnement proche de nombreux sites industriels. L’objectif principal de ce travail est l’amélioration des méthodologies de quantification des émissions des sources diffuses, notamment à partir d’une meilleure prise en compte de l’exposition éolienne des sources que sont les tas de stockage et des répartitions granulométriques des matières présentes sur les sites de stockage. Les observations sur sites industriels montrent que les régions proches des tas de stockage de matières granulaires sont chargées de particules de granulométries plutôt fines. Celles-ci sont susceptibles d’être remises en suspension par les structures tourbillonnaires générées par le vent incident. Ainsi, ces zones d’envol potentiel ont fait l’objet d’analyses afin de quantifier leur contribution aux émissions globales. Une technique de visualisation d’écoulement pariétal, associée à des simulations numériques tridimensionnelles, ont été mises en oeuvre pour mieux comprendre ces structures de l’écoulement. Les matières granulaires sont un mélange de particules érodibles et non-érodibles. Le caractère érodible étant lié aux propriétés des particules (principalement granulométrie et masse volumique), ainsi qu’à la vitesse du vent incident. Dans ce cadre, deux types d’études ont été menées: des essais expérimentaux d’envol de particules dans une soufflerie et des simulations numériques tridimensionnelles avec un logiciel open-source de mécanique des fluides (Code_Saturne). Une technique originale a ainsi été développée pour quantifier, par une pesée en continue, l’influence des particules non-érodibles sur le flux massique envolé. En parallèle, le comportement des particules sur la surface est analysé à l’aide de clichés photographiques. L’analyse de l’effet des particules non-érodibles au niveau local est réalisée grâce à des simulations numériques pour des configurations polydispersées. Les résultats présentés dans ce mémoire constituent de premiers éléments pouvant possiblement contribuer à l’amélioration des modèles actuels de quantification des émissions de particules par une meilleure intégration et pris en compte de la présence de particules non-érodibles pour les matières présentant de larges spectres granulométriques. / Wind erosion of granular materials (ores, coal, ...) is one of the factors that greatly influence the quality of the air in the immediate vicinity of many industrial sites. The main objective of this work is the improvement of methodologies for quantifying emissions from diffuse sources. It may be carried out by a better consideration of wind exposure on the sources (storage piles) and larger size distributions of granular materials present at the storage sites. Observations show that areas near storage piles of granular materials on industrial sites are loaded with silt particles. These particles may be re-emitted by vortex structures. Thus, these areas of potential particles take-off were analyzed to quantify their contribution to global emissions. A wall flow visualization technique associated with three-dimensional numerical simulations have been implemented. Granular material is a mixture of erodible and non-erodible particle. The erodible character may be associated to particle properties (mainly size and density), as well as the ambient wind speed. In this context, two types of studies were conducted: experimental tests of particles take-off in a wind-tunnel and numerical simulations with a three-dimensional open-source fluid dynamics code (Code_Saturne). An original technique has been developed to quantify, by a continuous weighing, the influence of non-erodible particles of the mass flow. In parallel, the behaviour of particles on the surface is analyzed using photographs. The analysis of the effect of nonerodible particles at local level is achieved through numerical simulations for poly-dispersed configurations. The results presented in this thesis are the first elements that can potentially contribute to the improvement of current models of quantification of particulate emissions through a better integration of the presence of non-erodible particles for materials with large particle size spectra.

Afin d'atteindre leur cible, les projectiles guidés d'artillerie nécessitent d'être dotés d'un dispositif de pilotage. Des surfaces de contrôle déployables et orientables sont donc nécessaires. Toutefois, le montage de gouvernes ajustables sur une ogive est une tâche mécaniquement ardue. En effet, lors du tir effectué par canon, l'équipement de bord subit une accélération significative, ce qui implique que des liaisons mécaniques particulièrement robustes doivent être conçues entre les ailettes et le corps. Cette technologie est bien maîtrisée lorsqu'elle est employée sur des projectiles de gros calibre, mais devient bien plus compliquée quand elle doit être adaptée pour être intégrée dans des petits ou moyens calibres. Néanmoins, dans des conditions de vol supersonique, des ondes de choc qui interagissent avec des surfaces solides sont susceptibles de considérablement modifier la distribution de pression. Ce principe a permis d'imaginer une méthode alternative de pilotage de projectiles supersoniques en exploitant des ondes de choc générées au moyen de petites perturbations créées à partir d'un micro-actionneur de forme cylindrique, aussi appelé micro-plot. Comme les forces de portance exercée sur un corps sont essentiellement dues à une pression appliquée sur de grandes surfaces, il a été choisi de se baser sur une configuration stabilisée par empennage. En vue de simplifier l'étude, le travail a été effectué sur un projectile académique de référence bien connu appelé le Basic Finner.Des expériences ont tout d'abord été effectuées dans la soufflerie supersonique de l'ISL sur une plaque plane comportant un plot et deux ailettes verticales. Ces mesures ont permis de valider la capacité de simulations numériques stationnaires RANS à prédire à la fois la distribution pariétale de la pression que génère un tel actionneur et le champ de vitesse de l'écoulement dans son voisinage. Les distributions de pression et de vitesse ont été mesurées en utilisant des méthodes optiques appelés Pressure Sensitive Paints (PSP) et Particle Image Velocimetry (PIV) afin d'être comparés avec les résultats de la CFD. Une étude paramétrique a ensuite été menée en se basant exclusivement sur ces simulations RANS. Ces calculs ont permis de déterminer l'emplacement optimal pour lequel le plot est le plus efficace sur toute l'enveloppe de vol du projectile. A partir de cette position optimale, deux configurations spécifiques ne générant aucun moment de roulis ont été étudiées numériquement et comparés en termes d'efficacité. En utilisant les coefficients aérodynamiques résultants de ce travail, des simulations de trajectoires à 6 degrés de liberté (6-DOF) ont été réalisées avec le code de BALCO (OTAN). Celles-ci ont permis de déterminer la déviation potentielle qui peut être obtenue sur une des deux configurations retenues en employant un tel micro-actionneur. Ces simulations 6-DOF ainsi que l'effet de du plot sur le projectile ont enfin été validés lors d'une campagne d'essai en vol libre qui a eu lieu sur le champ de tir de l'ISL. / In order to reach their target, guided artillery projectiles need some steering capability. Folding and adjustable control surfaces are thus necessary. However, mounting adjustable rudders on a shell is a difficult task, mechanically speaking. Indeed, during the gun launch, the onboard equipment undergoes significant acceleration so that robust mechanical joints have to be designed between the rudders and the body. This technique performs very well on large-caliber projectiles, but becomes more complicated when it has to be embedded in small- or medium-caliber ones. Nevertheless, under supersonic flight conditions, shock waves interacting with solid surfaces are likely to strongly modify the pressure distribution. This principle made it possible to imagine a way of steering small-caliber vehicles using shock waves generated by means of small disturbances created by a cylindrical-shaped micro-actuator, also called micro-pin. As lift forces exerted on a body are mainly due to the pressure applied to large surfaces, a finned configuration has been chosen. To simplify the study, the work has been conducted on the Basic Finner, a well known academic reference projectile.Experiments were first performed in the ISL supersonic wind tunnel on a flat plate on which a pin and two vertical projectile-like fins were mounted in order to validate the capability of steady RANS numerical simulations to predict both the pressure footprint of such an actuator and the flow velocity in its vicinity. Pressure and velocity distributions have been measured by using optical methods called Pressure-Sensitive Paint (PSP) and Particle Image Velocimetry (PIV) in order to be compared with the calculation results. A parametric study was then conducted with these RANS simulations so that the optimum location for which the pin is the most effective over the complete flight envelope of the projectile could be determined. Using this optimum position two specific no-roll momentum configurations were studied numerically and compared in terms of effectiveness. By using the aerodynamic coefficients resulting from this work, 6-Degree-Of-Freedom (6-DOF) trajectory simulations were performed with the NATO BALCO code on one of these configurations in order to determine the potential deviation which can be obtained with such an actuator. These 6-DOF simulations as well as the pin effect on the projectile could finally be validated during a free-flight campaign that took place at the ISL open-range testing site.

Aeroacoustic whistles are a significant source of customer complaints to automotive manufacturers. Whistles can occur on many such components, but the relative position and configuration of rearview mirrors means they are a more problematic source of tonal noise on vehicles. The low subsonic complex turbulent flow, combined with small cavity scales, determines the possible whistle mechanisms. The one considered to be most problematic, fluid-dynamic cavity resonance, is the topic of this research thesis. The research scope is limited to the automotive environment of external rearview mirrors and the fluid-dynamic resonance mechanism: low subsonic Mach number, M = 0.05 - 0.13; laminar boundary layers; and two-dimensional, acoustically compact cavities. The low unit-cost of rearview mirrors and the desire to have simple identification and prediction schemes, that could be used by production engineers, determined an empirical approach. A search of the existing literature revealed that there were some data on cavities of the above scale in low Mach number flow, but quoted errors in empirical descriptions were large and there was very little research on the effects of flow yaw angle on the chosen resonance mechanism. The research therefore aims to determine whether existing empirical descriptions of fluid-dynamic cavity resonance are suitable for the prediction of the resonance characteristics, with sufficient accuracy to enable unambiguous identification of the presence of the resonance and its mechanism. A second aim is to investigate the effects of a feature of the automotive flow environment, flow yaw angle, on the resonance. Flow yaw angle is determined by those components of the flow in the same plane as the surface in which the cavity is situated. An experimental program was undertaken using a purpose-built aeroacoustic wind tunnel and a simple cavity model. Testing with two types of cavity configurations, as well as flow visualisation, investigated the main features of the resonance in time-averaged yawed flow. Within the scope of this thesis, it is shown that fluid-dynamic cavity resonance characteristics can be accurately identified by a simple empirical model, even in yawed flow. Various descriptors allow identification of the resonance threshold, stage, frequency and relative amplitude in non-yawed flow, while the frequency and stage can also be identified in yawed flow. The relative decrease in resonance amplitude in yawed flow, although identified for these experiments, would depend on the degree of spanwise variation in the boundary layer characteristics for a given cavity configuration. The results also identify significant issues with testing in a free jet tunnel, due to the nature of fluid-dynamic cavity resonance and the fluctuation energy content in free shear layers. Despite this, the thesis aims are achieved, and appropriate design guidelines are produced for automotive designers.

In this thesis, aeroelastic concepts for increased aircraft performance are developed and evaluated. Active aeroelastic concepts are in focus as well as robust analysis concepts aiming at efficient analysis using numerical models with uncertain or varying model parameters. The thesis presents different approaches for exploitation of fluid-structure interaction of active aeroelastic structures. First, a high aspect ratio wing in wind tunnel testing conditions is considered. The wing was developed within the European research project \textit{Active Aeroelastic Aircraft Structures} and used to demonstrate how structural flexibility can be exploited by using multiple control surfaces such that the deformed wing shape gives minimum drag for different flight conditions. Two different drag minimization studies are presented, one aiming at reduced induced drag based on numerical optimization techniques, another one aiming at reduced measured total drag using real-time optimization in the wind tunnel experiment. The same wing is also used for demonstration of an active concept for gust load alleviation using a piezoelectric tab. In all studies on the high aspect ratio wing, it is demonstrated that structural flexibility can be exploited to increase aircraft performance. Other studies in this thesis investigate the applicability of robust control tools for flutter analysis considering model uncertainty and variation. First, different techniques for taking large structural variations into account are evaluated. Next, a high-fidelity numerical model of an aircraft with a variable amount of fuel is considered, and robust analysis is applied to find the worst-case fuel configuration. Finally, a study investigating the influence of uncertain external stores aerodynamics is presented. Overall, the robust approach is shown to be capable of treating large structural variations as well as modeling uncertainties to compute worst-case configurations and flutter boundaries. / QC 20100713