As pesquisas modernas em aeronáutica envolvem a expansão dos envelopes de vôo, como resultado do desejo de melhorar a manobrabilidade e controlabilidade em operações táticas, e melhorar a segurança do vôo. Esses objetivos podem ser alcançados através do desenvolvimento de sistemas automáticos de controle de vôo. Os sistemas de controle aplicados a aeronaves podem ser desenvolvidos e simulados através de métodos computacionais. No entanto, existem imperfeições na simulação computacional por não se conseguir reproduzir algumas características do vôo real ou devido a simplificações no modelo matemático da aeronave. Desta forma, a construção de um modelo físico de uma aeronave em escala reduzida e a implementação de um controlador a este modelo, torna-se uma ferramenta bastante importante para validar resultados teóricos e métodos computacionais. Os custos associados a estes testes são geralmente muito menores que aqueles dos ensaios em vôo e com maior flexibilidade de instrumentação. Este trabalho descreve a construção de um modelo de aeronave, baseado no X-29, o desenvolvimento de um mecanismo de fixação do modelo ao túnel de vento, tipo rótula, e a implementação de um sistema de aumento de estabilidade longitudinal, através de um sistema de controle automático. O modelo físico possui uma configuração de asa com enflechamento negativo e canard, e que tende a ser inerentemente instável, sendo necessário o auxílio de um sistema de aumento de estabilidade. Testes de estabilidade dinâmica em arfagem foram realizados no túnel de vento em diferentes posições do centro de gravidade. Os parâmetros de estabilidade foram registrados e analisados através de uma curva de ajuste exponencial. / Modern aeronautical research involves flight envelope expansion as the result of a desire for improvement in tactical operation handling qualities and improvement in flight safety. These objectives can be achieved through the development of automatic flight control systems. Aircraft flight control systems can be developed and simulated through computational methods. However, there are imperfections in the computational simulation of flight dynamics due to the difficulty in reproducing real flight conditions or due simplifications in the aircraft mathematical model. The construction of a reduced scale physical aircraft model and the implementation of a controller is a very valuable tool to validate theoretical results and computational methods. The costs associated with these tests are usually much smaller than those associated with full scale flight testing and may offer greater flexibility for instrumentation. The present work describes the construction of an airplane model, based on the X-29, the development of a wind tunnel gimbal type support and the implementation of a longitudinal stability augmentation system using automatic flight control. The model configuration has forward swept wings and canard with a tendency to be inherently unstable and, thus, requiring a stability augmentation system. Pitching dynamic stability tests where conducted in a wind tunnel in different center of gravity positions. Stability parameters were acquired and analyzed by exponential fit curve.

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.

In canonical boundary layer transition, a uniform laminar flow perturbed by 2-d T-S waves develops downstream into 3-d waves, which eventually break down with turbulent spots appearing. Previous experimental studies have established that this kind of development is absent, is by-passed, in transition induced by free-stream turbulence or surface roughness. However a common, characteristic feature of the late, three-dimensional stage is the prevalence of streamwise vorticity and streaks. Isolated and multiple streamwise vortices are present in both, canonical transition and bypass transition. This thesis de-scribes an experimental study of the late stages of boundary layer transition after a single or a pair of streamwise vortices have formed. The present work can be considered both as a study of transition induced by surface roughness and as a study of the late stages of transition in general. The experiments were made on a zero-pressure-gradient boundary layer in a low speed wind tunnel. Various hill configurations, mounted on a flat plate, were used to create isolated and multiple streamwise vortices. Particle image velocimetry (PIV) and hot-wire anemometry used for measurements. Numerical simulations of the initial laminar stage were carried out to understand the vortex formation at the edge of the hills. Computations have shown that the streamwise vorticity induced by the spanwise asymmetry of the hill rolls up into a single streamwise vortex. The streamwise vortex causes high speed fluid to be brought close to the wall and low speed fluid to move away. In turn, streamwise velocity profiles acquire inflections in both the spanwise and wall-normal directions. Previous studies have concluded that the inviscid instability of inflectional profiles are essential, or at least common, precursors to transition. Another view of the structure of bypass transition induced involves a secondary instability of streaks that can be sinuous or varicose. These two types follow from instabilities of the inflectional spanwise and wall-normal profiles of the streamwise velocity, respectively. However the present study confirms that the occurrence of inflections is not sufficient for transition. The first series of experiments were with smooth Gaussian shaped hills that spanned one-half of the tunnel. Two hill shapes were taken, steep and shallow. Isolated streamwise vortices formed by the side of the hill. Hill heights were less than that of the incoming boundary layer, and they were mounted within the subcritical part of the boundary layer. At low free stream speeds, streaks formed, with inflectional wall-normal and spanwise velocity profiles, but without effecting transition. The necessary conditions for inviscid instability Rayleigh’s inflexion-point theorem and Fjortoft’s theorem are satisfied for these low-speed non-transitional cases. Transition observed at higher speeds show two kinds of development. With the steep hill, the streamwise vortex is not too close to the plate and it exhibits oscillations over some distance before flow breaks down to turbulence; streamwise velocity signals exhibited the passage of a wave packet which intensified before break-down to turbulence. This dominant mode persists far downstream from the hill even while the flow breaks down and frequency content grows over a range of scales. With the shallow hill, the breakdown develops continuously without such a precursor stage; there was a broad range of frequencies present immediately downstream of the hill. For the steep hill the maximum fluctuation is observed on the upwash side of the vortex. With the shallow hill, the fluctuation level is maximum at the location between low and high speed streak. Features of breakdown to transition caused by these single streamwise vortices are found to be similar to those in transition by other causes such as surface roughness, freestream turbulence etc. With the steep hill, the growth of fluctuations(urms, the peak levels of streamwise velocity component fluctuations) is remarkably similar to that in the K-type transition. Unlike in freestream induced transition, the initial growth of u2 rms,max with downstream distance was not linear. Profiles of urms/urms,max vs. y/δ∗where δ∗,is the displacement thickness is partially matching with the optimal disturbances, for the steep hill case. The phase velocity matches as in previous measurements of roughness induced transition. The flow exhibits the breakup of a shear layer near the outer edge of the boundary layer into successive vortices. This breakdown pattern resembles to those in the recent numerical simulations. The passing frequency of these vortices scales with freestream velocity, similar to that in single-roughness induced transition. Quadrant analysis of streamwise and wall-normal velocity fluctuations show large ejection events in the outer layer. The difference in the route to transition between the steep and shallow hills was considered to the relative proximity of the initial streamwise vortex to the flat plate and its interaction with the wall. To examine this conjecture, two configurations were prepared to produce two types of counter-rotating streamwise vortices. One is a hill that span the tunnel except for a short gap, and the other, its complement, is a short span hill. The short-gap hill produce a pair of vortices with the common flow directed away from the wall. This resulted in a separation bubble that formed a short distance downstream and breakdown to turbulence. The short-span hill configuration seems to have a stabilizing effect. With the short gap hill, transition occurs for lower freestream speeds than with the isolated vortices considered before. Also, the breakdown location is further downstream when the gap is larger. The initial velocity profiles look similar for transitional and non-transitional flow cases, and are inflectional, which clearly indicates that inflectional instabilities are not effective here. A separation index was computed to identify unsteadiness of the separated flow region. The separation is itself steady, where as the reattachment is unsteady. Fluctuations grow near this reattachment zone. The unsteadiness of the reattachment coexists with the appearance of strong fluctuations and transition. It is likely that the this last stage of breakdown results when the shear layer, lifted up by the separation bubble, breaks down near the edge of the boundary layer and the consequent unsteadiness is in the reattachment also. Coherent cat’s-eye-like patterns were observed in a longitudinal, plane normal to the wall. With isolated vortices sinuous oscillations and with stream-wise vortex pairs varicose oscillations were observed in wall-parallel planes. In both cases passing frequency of these vortices scales with freestream velocity. Λ-type vortices were identified in spanwise plane with counter-rotating legs. These experiments have identified some possible roles of streamwise vortices in the last stages of boundary layer transition. Vortices may undergo their own instability in the background shear layer, evident as oscillations, if they are not too close to the wall. Otherwise the breakdown is without such a stage. Wall interaction of these vortices seems to be a necessary last stage. Inflectional instability is not indicated. Wall interaction that results in separation results in break-down in the unsteady reattachment zone. Breakdown coexists with the reattachment and not at separation, even though it may be the separating shear layer that breaks down.

La modélisation inverse de la dispersion atmosphérique consiste à reconstruire les caractéristiques d’une source (quantité de polluants rejetée, position) à partir de mesures de concentration dans l’air, en utilisant un modèle direct de dispersion et un algorithme d’inversion. Nous avons utilisé dans cette étude deux modèles directs de dispersion atmosphérique SIRANE (Soulhac, 2000; Soulhac et al., 2011) et SIRANERISK (Cierco et Soulhac, 2009a; Lamaison et al., 2011a, 2011b). Il s’agit de deux modèles opérationnels de « réseau des rues », basés sur le calcul du bilan de masse à différents niveaux du réseau. Leur concept permet de décrire correctement les différents phénomènes physiques de dispersion et de transport de la pollution atmosphérique dans des réseaux urbains complexes. L’étude de validation de ces deux modèles directs de dispersion a été effectuée après avoir évalué la fiabilité des paramétrages adoptés pour simuler les échanges verticaux entre la canopée et l'atmosphère, les transferts aux intersections de rues et la canalisation de l’écoulement à l’intérieur du réseau de rues. Pour cela, nous avons utilisé des mesures en soufflerie effectuées dans plusieurs configurations académiques. Nous avons développé au cours de cette thèse un système de modélisation inverse de dispersion atmosphérique (nommé ReWind) qui consiste à déterminer les caractéristiques d’une source de polluant (débit, position) à partir des concentrations mesurées, en résolvant numériquement le système matriciel linéaire qui relie le vecteur des débits au vecteur des concentrations. La fiabilité des résultats et l’optimisation des temps de calcul d’inversion sont assurées par le couplage de plusieurs méthodes mathématiques de résolution et d’optimisation, bien adaptées pour traiter le cas des problèmes mal posés. L’étude de sensibilité de cet algorithme d’inversion à certains paramètres d’entrée (comme les conditions météorologiques, les positions des récepteurs,…) a été effectuée en utilisant des observations synthétiques (fictives) fournies par le modèle direct de dispersion atmosphérique. La spécificité des travaux entrepris dans le cadre de ce travail a consisté à appliquer ReWind dans des configurations complexes de quartier urbain, et à utiliser toute la variabilité turbulente des mesures expérimentales obtenues en soufflerie pour qualifier ses performances à reconstruire les paramètres sources dans des conditions représentatives de situations de crise en milieu urbain ou industriel. L’application de l’approche inverse en utilisant des signaux instantanés de concentration mesurés en soufflerie plutôt que des valeurs moyennes, a montré que le modèle ReWind fournit des résultats d’inversion qui sont globalement satisfaisants et particulièrement encourageants en termes de reproduction de la quantité de masse totale de polluant rejetée dans l’atmosphère. Cependant, l’algorithme présente quelques difficultés pour estimer à la fois le débit et la position de la source dans certains cas. En effet, les résultats de l’inversion sont assez influencés par le critère de recherche (d’optimisation), le nombre de récepteurs impactés par le panache, la qualité des observations et la fiabilité du modèle direct de dispersion atmosphérique. / The aim of this study is to develop an inverse atmospheric dispersion model for crisis management in urban areas and industrial sites. The inverse modes allows for the reconstruction of the characteristics of a pollutant source (emission rate, position) from concentration measurements, by combining a direct dispersion model and an inversion algorithm, and assuming as known both site topography and meteorological conditions. The direct models used in these study, named SIRANE and SIRANERISK, are both operational "street network" models. These are based on the decomposition of the urban atmosphere into two sub-domains: the urban boundary layer and the urban canopy, represented as a series of interconnected boxes. Parametric laws govern the mass exchanges between the boxes under the assumption that the pollutant dispersion within the canopy can be fully simulated by modelling three main bulk transfer phenomena: channelling along street axes, transfers at street intersections and vertical exchange between a street canyon and the overlying atmosphere. The first part of this study is devoted to a detailed validation of these direct models in order to test the parameterisations implemented in them. This is achieved by comparing their outputs with wind tunnel experiments of the dispersion of steady and unsteady pollutant releases in idealised urban geometries. In the second part we use these models and experiments to test the performances of an inversion algorithm, named REWind. The specificity of this work is twofold. The first concerns the application of the inversion algorithm - using as input data instantaneous concentration signals registered at fixed receptors and not only time-averaged or ensemble averaged concentrations. - in urban like geometries, using an operational urban dispersion model as direct model. The application of the inverse approach by using instantaneous concentration signals rather than the averaged concentrations showed that the ReWind model generally provides reliable estimates of the total pollutant mass discharged at the source. However, the algorithm has some difficulties in estimating both emission rate and position of the source. We also show that the performances of the inversion algorithm are significantly influenced by the cost function used to the optimization, the number of receptors and the parameterizations adopted in the direct atmospheric dispersion model.

Le Sous-comité de la conception et de la construction navale de l'Organisation maritime internationale (OMI) a entrepris l'élaboration de critères de stabilité intacts de deuxième génération (SGISC). Le SGISC est une règle supplémentaire qui complète les règles actuelles.En outre, ces critères sont structurés en trois niveaux, à savoir le premier niveau, le deuxième niveau et l'évaluation directe. Les procédures d'évaluation directe pour chaque échec de stabilité sont développées avec la technologie de pointe la plus avancée disponible soit par analyse numérique, soit par travail expérimental pour une analyse quantitative. Dans cette thèse, on présente une implémentation des niveaux 1 et 2 du SGISC dans le solveur hydrostatique, une approche expérimentale pour le navire en détresse dans une tempête et des simulations RANS du même critère. En conclusion, il est possible de mettre en oeuvre les critères de stabilité du navire intact de deuxième génération dans le code de stabilité GHS ©, un code couramment utilisé par les industriels dans le domaine. Cinq navires ont été considérés pour vérifier cette mise en oeuvre. Une méthode expérimentale utilisant une grande soufflerie et une méthode de calcul CFD simplifiée ont été appliquées sur deux modèles. Dans les deux cas, les résultats montrent que l'angle de roulis maximal atteint par les deux navires étudiés est inférieur à celui donné par le calcul réglementaire. La méthode expérimentale est certainement plus proche de la réalité et le calcul CFD reste conservateur sans être aussi contraignant que la réglementation. En conclusion les méthodes expérimentale et numérique développées et utilisées dans ce travail de thèse peuvent être proposées pour l’évaluation directe du critère. / The Sub-Committee of Ship Design and Construction of International Maritime Organisation (IMO) has undertaken the development of Second Generation Intact Stability Criteria (SGISC). The GISC is an additional rule that complement present rules. Five failure modes will be address in SGISC are excessive roll in dead ship condition, pure loss of stability, broaching, parametric roll, and excessive acceleration. Moreover, these criteria are structured in three levels namely, first level, second level and direct assessment. Direct assessment procedures for every stability failure are developed with the most advanced state-of-the art technology available either by numerical analysis or experimental work for quantitative analysis. In this thesis, implementations of Level 1 and Level 2 of the SGISC in the hydrostatic solver, experimental approached for dead ship condition and RANS simulation are presented.In conclusion, it was possible to implement the stability criteria of the intact second-generation vessel in the GHS © code of stability, a code commonly used by industrialists in the field. Five vessels were considered to verify this implementation. An experimental wind tunnel method and a simplified CFD calculation method were used on two different models. In both cases, the results show that the maximum roll angle reached by the two vessels studied is lower than the one given by the regulatory calculation. The experimental method is certainly closer to reality and the calculation CFD remains conservative without being as binding as the regulation.Therefore, the two approaches, numerical and experimental can be proposed to be used for Direct Assessment of the criterion.

A l’heure actuelle, seuls des facteurs locaux, stationnels, sont considérés pour le calcul des risques liés au vent alors que le vent qui aborde un peuplement forestier est affecté par les surfaces sur lesquelles il vient de passer ; les lisières en particulier jouent un rôle important sur l’écoulement atmosphérique, en contribuant à générer de la turbulence. Dans un paysage fragmenté, constitué d’une mosaïque de surfaces de différentes hauteurs et rugosités, la multiplicité des lisières est ainsi susceptible d’avoir des effets cumulatifs perceptibles à l’échelle régionale, qui pourraient contribuer de manière significative à la fragilité des massifs face à des tempêtes. Certains niveaux de fragmentation semblent susceptibles de conduire à un accroissement des risques en cas de vent violent. Bien que la région de lisière a été étudiée de manière approfondie dans le passé en raison de leur importance pour la détermination des vitesses de vent, des niveaux de turbulence et des échanges entre l’atmosphère et la canopée, il n’y a aucune étude de l’impact de lisières multiples ou de la fragmentation des forêts sur les caractéristiques de la couche limite à l’échelle du paysage. Quelques rares études laissent penser que la fragmentation du paysage pourrait moduler de manière significative la structure turbulente de la couche limite atmosphérique mais ces études concernent des réseaux de brisevents plutôt qu’un ensemble de parcelles forestières. On cherche par conséquent à caractériser les champs de vent et de turbulence pour ces différentes configurations. Pour ce faire, une expérimentation en soufflerie à été réalisée, visant à caractériser l’écoulement sur des maquettes de paysage présentant cinq degrés de fragmentation (L = ~ 5, ~ 10, ~15, ~20, ~30h, où L est la distance entre deux patchs de forêts régulièrement espacés et h est la hauteur de la canopée). Un cas homogène a également été simulé et sert ici de référence. Pour le modèle de canopée choisi, ces expérimentations montrent que l’énergie cinétique turbulente présente dans la basse atmosphère ne passe pas par un maximum pour une valeur de l’espacement intermédiaire comme il était supposé à l’origine. Le cas homogène est la configuration la plus rugueuse. Pour de grands espacements l’influence d’une parcelle ne se fait guère sentir sur la suivante et lorsqu’ils sont faibles l’écoulement ne "ressent" guère les clairières et présente des caractéristiques semblables au cas homogène. Nous avons également évalué un modèle atmosphérique de type "simulation des grandes échelles" à l’aide des données présentées précédemment. Le modèle est capable de reproduire les grandes caractéristiques de la turbulence telles que les vitesses de vent horizontales et verticales, l’énergie cinétique turbulente, les contraintes de Reynolds et les coefficients d’asymétrie horizontale et verticale en tous points du domaine. Cela nous a permis de confirmer la validité des calculs numériques et de simuler l’écoulement sur une plus large gamme de paysages fragmentés. Les résultats démontrent l’importance de l’indice foliaire pour le calcul de la rugosité effective sur une succession de patchs de forêt. / At present only the characteristics of a forest stand and its immediate environment are taken into account in calculating forest wind risk. However, it is known that the wind is strongly affected by the surfaces over which it has previously flowed. Forest edges in particular play an important role in determining the characteristics of the atmospheric flow by generating increased turbulence, triggering the formation of coherent tree scale structures. In a fragmented landscape, consisting of surfaces of different heights and roughness, the multiplicity of edges may have cumulative effects at the regional scale leading to increased forest damage during storms. Flow changes in the atmospheric boundary-layer across surface roughness changes have received extensive study in the past because of their importance in determining velocities, turbulence levels and exchange between the atmosphere and biosphere or ground. There have also been a number of studies across single forest edges both in the field, wind-tunnels and computer models. However, there have been no studies of flow across multiple forest edges or the impact of forest fragmentation on the characteristics of the boundary-layer. The only studies on multiple surface changes have been wind-tunnel examination of the flow though and across multiple wind-breaks. In this thesis we show results from a series of wind tunnel experiments on a range of levels of forest fragmentation. Five gap spacings (L = ~ 5, ~ 10, ~15, ~20, ~30h, where L is the length of the gap and h is the canopy height) were investigated using 3D laser doppler velocimetry in order to assess the effects of fragmented landscapes on mean and turbulent wind characteristics. The fragmentation was two-dimensional with the transition between forest and gaps only being along the wind direction and the forest and gaps were continuous perpendicular to the wind direction. The wind speeds and turbulence characteristics are compared against measurements from a single forest edge in the wind tunnel, which acts as a reference. No enhancement of turbulence formation at a particular level of fragmentation was observed but there was a consistent pattern of wind speed and turbulence back from the first edge of each simulation with the horizontal velocity at tree top increasing and the turbulent kinetic energy decreasing as gap size increased. We also compare mean wind speeds (U and W) and turbulence characteristics (variance in u, v, and w; skewness in U, V, and W; Reynold’s stress, and TKE) at all points in the experimental measurement domain of the wind tunnel with Large Eddy Simulation (LES) results, which allows us to confirm the validity of the LES calculations and to conduct a wider range of experiments than was possible in the wind-tunnel. The results demonstrate the importance of the frontal area index or roughness density of elements (in this case trees) in determining the nature of the flow and the effective roughness of the overall surface. They also show that as the gaps between forest blocks increases the flow transitions (at a gap size between 10 to 15 tree heights) from flow comparable to that over a continuous forest to flow across a set of isolated forest blocks.

Widespread damage to roofing materials (such as tiles and shingles) for low-rise buildings, even for weaker hurricanes, has raised concerns regarding design load provisions and construction practices. Currently the building codes used for designing low-rise building roofs are mainly based on testing results from building models which generally do not simulate the architectural features of roofing materials that may significantly influence the wind-induced pressures. Full-scale experimentation was conducted under high winds to investigate the effects of architectural details of high profile roof tiles and asphalt shingles on net pressures that are often responsible for damage to these roofing materials. Effects on the vulnerability of roofing materials were also studied. Different roof models with bare, tiled, and shingled roof decks were tested. Pressures acting on both top and bottom surfaces of the roofing materials were measured to understand their effects on the net uplift loading. The area-averaged peak pressure coefficients obtained from bare, tiled, and shingled roof decks were compared. In addition, a set of wind tunnel tests on a tiled roof deck model were conducted to verify the effects of tiles’ cavity internal pressure. Both the full-scale and the wind tunnel test results showed that underside pressure of a roof tile could either aggravate or alleviate wind uplift on the tile based on its orientation on the roof with respect to the wind angle of attack. For shingles, the underside pressure could aggravate wind uplift if the shingle is located near the center of the roof deck. Bare deck modeling to estimate design wind uplift on shingled decks may be acceptable for most locations but not for field locations; it could underestimate the uplift on shingles by 30-60%. In addition, some initial quantification of the effects of roofing materials on wind uplift was performed by studying the wind uplift load ratio for tiled versus bare deck and shingled versus bare deck. Vulnerability curves, with and without considering the effects of tiles’ cavity internal pressure, showed significant differences. Aerodynamic load provisions for low-rise buildings’ roofs and their vulnerability can thus be more accurately evaluated by considering the effects of the roofing materials.

No description available.

The thesis deals with Formula Student cooling system. The thesis is divided to three main parts, the first part deal about description of current cooling system and lubricating system. The second part of thesis deals with measuring individual component of system at measuring stand, wind tunnel and measuring at vehicle. The last part of thesis deal about evaluation of measurement and construction changes for improving parameters of the cooling system.

Actuellement, le dépôt sec d’aérosols en milieu urbain est peu connu du fait d’un manque de données.Ces connaissances sont pourtant indispensables pour comprendre les flux de polluants dans les villes et estimer l’exposition d’habitants à des rayonnements ionisants dans le cas d’aérosols radioactifs. Un apport de données permettrait en outre d’améliorer la modélisation du dépôt dans ce milieu. Une approche expérimentale originale est employée pour étudier le dépôt sec d’aérosols submicroniques sur des surfaces urbaines. L’association d’expérimentations en soufflerie et in situ et l’utilisation de traceurs permettent de mesurer des vitesses de dépôt sec et d’étudier les différents phénomènes physiques qui régissent ce dépôt en milieu urbain. Ces données sont associées à des conditions de météorologie et de turbulence quantifiées par des mesures. Cet ensemble permet de hiérarchiser l’influence des principaux phénomènes physiques pour chaque type d’expérimentation. Notamment,des phénomènes différents doivent être considérés prépondérants dans le cas d’expositions chroniques ou aigües des surfaces urbaines aux particules atmosphériques. / Aerosol dry deposition is not much known for urban areas due to the lack of data. Knowledge on this phenomenon is necessary to understand pollutant fluxes in cities and to estimate inhabitant exposition to ionizing radiation of radioactive aerosols. A data providing could enable to enhance dry deposition models for these areas. An original experimental approach is performed to study submicron aerosol dry deposition on urban surfaces. Wind tunnel coupled to in situ experiments give results to study different physical phenomen on governing dry deposition. Dry deposition velocities are measured using aerosol tracers. These data are associated to turbulent and meteorological measured conditions. This database permits to classify the principal physical phenomenon for each experiment type. Finally, different phenomenon must be considered for chronic and acute exposition of urban surfaces to atmospheric particles.