L’aile rigide navale est le moyen de propulsion qui se substitue à la grande voile souple sur les catamarans de classe Coupe de l’América et Class-C. Ce gréement est similaire à une aile aéronautique, composée de deux éléments, avec le volet séparé de l’élément principal par une fente. Comparée à une voile souple, l’aile rigide permet d’améliorer les performances du bateau en naviguant à des vitesses plus grandes que celle du vent. Cependant, le décrochage brutal qui caractérise l’aile et sa sensibilité à l’instationnarité du vent rendent difficile la correcte maîtrise de l’aile pendant la navigation. La modification des forces aérodynamiques qui agissent sur l’aile, dû à l’action d’une rafale ou au dépassement de la limite du décrochage, peuvent compromettre la stabilité du catamaran avec un possible risque de chavirage. L’aile doit donc être dessinée et réglée correctement pour éviter cette possibilité de chavirage, mais il est nécessaire de connaître l’enveloppe aérodynamique. / Wingsail is a propulsion system substituting the conventional main soft sail on the America’s Cup and C-class catamarans. This rig is similar to a slotted-flap aeronautical wing, made by two elements divided by a slot. With respect to soft sails, the wingsail improves the performance of the yachts allowing navigating faster than the wind in both the upwind and downwind points of sail. However, the abrupt stall characteristics of the wing and its sensitiveness to the wind unsteadiness make difficult its management during the navigation. The modification of the strength of the aerodynamic forces acting on the wingsail, due to a gust or to the achievement of the stall limit, can compromise the stability of the catamaran. Thus, the wingsail has to be designed and trimmed to avoid the possibility of a capsize but, to do this, the aerodynamic envelop of the wingsail must be known. The aim of the Ph.D. project is, hence, to characterize the flow around the wingsail investigating the influence of the geometric and trim parameters on the wing performance.

Tempestades severas ocorrem na Região Metropolitana de São Paulo (RMSP) principalmente nos meses quentes e úmidos do ano. Nesta tese, os mecanismos de disparo da convecção profunda são estudados por meio de análises observacionais e simulações numéricas com o Advanced Regional Prediction System (ARPS). A metodologia proposta compreende o uso da parametrização microfísica fria na simulação dos processos físicos que levam à formação de nuvens cumulonimbus, sem o uso da parametrização de cúmulos nas grades de altíssima resolução espacial. Nos eventos estudados, as primeiras células de precipitação observadas e simuladas surgiram em razão da interação entre o escoamento atmosférico na camada limite planetária e a topografia local. As células secundárias foram geralmente mais intensas, uma vez que elas surgiram após o aquecimento diabático adicional. O mecanismo de disparo das células secundárias foi a corrente ascendente induzida pela propagação horizontal das frentes de rajada em baixos níveis da atmosfera das correntes descendentes das células primárias. As frentes de rajada tiveram velocidade de propagação horizontal típica de 6 m s-1. No evento de 02 de fevereiro de 2004, células convectivas profundas foram simuladas com alto grau de realismo no domínio da grade de 3 km de resolução espacial. Observou-se que, neste caso, a frente de brisa marítima pôde atuar como guia de ondas para a colisão entre duas frentes de rajada. A propagação da frente de brisa marítima para o interior do continente ocorreu em conjunção a um forte gradiente de vapor dágua nos níveis mais baixos da troposfera. As células convectivas profundas secundárias surgiram e se desenvolveram exatamente nesta zona de interface, a qual representa o contraste entre as diferentes massas de ar marítima e continental. No evento de 04 de fevereiro de 2004, na grade de 1 km de resolução, a análise objetiva com as medidas das estações de superfície na RMSP correspondente às 1800 UTC indicou a presença de uma ilha de calor urbana com até 4 oC de aquecimento diferencial entre a Capital e vizinhanças. O principal efeito da assimilação destas medidas foi a redução do NCL em até 80 hPa, o que favoreceu o disparo da convecção naquela área. / Severe thunderstorms occur in the Metropolitan Area of São Paulo (MASP) mainly in the warm and wet months of the year. In this work, the triggering mechanisms of deep convection are studied through observed data and numerical simulations with the Advanced Regional Prediction System (ARPS). The proposed methodology focuses in the use of microphysics parameterization of cold clouds to simulate physical process linked to the life cycle of thunderstorms. The cumulus cloud parameterization isnt used in high resolution numerical grids. In the real case studies, both observed and simulated, early convective cells developed as a consequence of the interaction between the planetary boundary layer atmospheric flow and the local topography. The secondary convective cells were generally strongest, once they developed after additional surface diabatic heating. The triggering mechanism of these secondary cells was the updraft induced by gust fronts generated by downdrafts of primary cells. The gust fronts had a typical horizontal propagation velocity of 6 m s-1. In the February 02 2004 event, deep convective cells were simulated with high degree of realism with a 3 km resolution grid. It was observed that, in this case, the sea-breeze front could act as a wave guide to the collision between two different gust fronts. In addition, the sea breeze front propagated to the continental area together with a strong low level water vapor gradient. The secondary deep convective cells arose and developed exactly on this interface zone, which represents the contrast between the oceanic and continental air masses. The interface zone was marked by a water vapor mixing rate of 14 g kg-1. In the February 04 2004 event, the objective analysis, made with some MASP´s surface stations measurements at 1800 UTC in the 1 km resolution grid, indicates the presence of an urban heat island with up to 4 oC of differential heating between São Paulo city and its neighboring area. The main effect in assimilating these surface measurements was the lowering of the lift condensation level up to 80 hPa, which favored the triggering of convection in that area.

Tématem diplomové práce je koncepční studie lehkého dvoumotorového letounu. Je provedeno srovnání současných letounů, jejich motorů, technický popis navrhovaného řešení, hmotový rozbor, výpočet aerostatických podkladů, výpočet obálky zatížení, nákladů na vývoj a základní konstrukce hlavních součástí.

Orientador: Douglas Domingues Bueno / Resumo: Os fenômenos associados aos sistemas aeroelásticos definem uma importante classe de problemas envolvida no projeto de aeronaves. Algumas análises podem ser realizadas utilizando a formulação no domínio da frequência, porém, para alguns problemas específicos a análise no domínio do tempo mostra-se mais conveniente, especialmente para projeto de controladores e inclusão de não linearidades. Em particular, forças aerodinâmicas não estacionárias são tipicamente obtidas no domínio da frequência reduzida. Tais formulações não permitem de maneira direta, através de uma transformada inversa, obter modelos matemáticos no domínio do tempo e, portanto, é necessário o uso de um método de aproximação, como o de Roger-Abel. No entanto, uso deste método de aproximação apresenta algumas lacunas com relação ao significado físico e escolha dos parâmetros de atraso. Desta forma, o presente texto explora a influência dos estados de atraso demonstrando que é responsável pela correção da fase entre o movimento e as forças aerodinâmicas resultantes e, também, propõe uma forma de avaliação da qualidade da aproximação obtida. A partir da aproximação das cargas aerodinâmicas se obtém o modelo matemático do sistema aeroelástico, e através de simulações numéricas computacionais, tem-se a resposta do sistema aeroelástico no domínio do tempo devido à cargas de rajada $1-cosseno$. A partir da análise da resposta à rajada é possível avaliar condições em que a rajada se apresenta de maneira mais crítica para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The phenomena associated with the aeroelastic systems define an important class of problems involved in aircraft design. Some analyzes may be performed in the frequency domain, however, for some specific problems time domain analysis is more convenient, especially for controller design and the inclusion of nonlinearities. In particular, non-stationary aerodynamic forces are typically obtained in the reduced frequency domain. Such formulations do not allow, by means of an inverse transform, to obtain mathematical models in the time domain, and therefore it is necessary to use an approximation method, such as that of Roger-Abel. However, the use of this approximation method presents some gaps with respect to the physical meaning and choice of lag parameters. In this way, the present text explores the influence of the lag states demonstrating that it is responsible for the correction of the phase between the movement and the resulting aerodynamic forces and also proposes a method to evaluate the quality of the approximation achieved. From the approximation of the aerodynamic loads the mathematical model of the aeroelastic system is obtained, and through computational numerical simulations, has the response of the aeroelastic system in the time domain due to the 1-cosine gust load. From the analysis of the response to the gust, it is possible to evaluate conditions in which the gust is presented in a more critical way for the study system. / Mestre

D'entre els defectes organolèptics associats al vi, en destaca l'anomenat "gust de suro" habitualment vinculat a la presència de cloroanisoles, els quals són productes de l'activitat microbiana formats a partir dels corresponents clorofenols. La present tesi doctoral recull, en primer lloc, metodologies analítiques adreçades principalment a la determinació dels compostos clorofenòlics (2,4,6-triclorofenol, 2,3,4,6-tetraclorofenol i pentaclorofenol) en el control de qualitat dels taps suro, emprant dissolucions hidroalcohòliques com a medi de maceració o d'extracció i utilitzant les tècniques d'extracció en fase sòlida (SPE) i microextracció en fase sòlida (SPME) acoblades a la cromatografia de gasos (GC).En segon lloc, per tal de dur a terme l'anàlisi de cloroanisoles juntament amb els seus precursors en matrius de suro s'ha avaluat un mètode basat en l'extracció amb dissolvent orgànic, el qual ha estat aplicat per a l'estudi de diferents sistemes d'eliminació d'aquests anàlits en la matriu citada. En darrer lloc, s'han proposat metodologies per l'anàlisi de mostres de vi, en les quals d'una banda s'han determinat els compostos clorofenòlics utilitzant la SPME i de l'altra el 2,4,6-tricloroanisole i el 2,4,6-tribromoanisole mitjançant l'acoblament de la SPE i la injecció de grans volums (LVI) en el sistema cromatogràfic. / The organoleptic defect known as cork taint is associated with a musty or mouldy aroma in wine. Chloroanisoles, which are produced through a process of detoxification by fungal methylation of chlorophenolic compounds, are considered to be the main contributory substances. In the present work, analytical methods for the determination of chlorophenols (2,4,6-trichlorophenol, 2,3,4,6-tetrachloropheol and pentachlorophenol) in cork matrices using the solid-phase extraction (SPE) and the solid-phase microextraction (SPME) as preconcentration techniques were evaluated. Therefore, hydroalcoholic solutions have been proposed as extractant solvent in order to test the quality of cork stoppers.Furthermore, a methodology based on extraction with an organic solvent for the simultaneous determination of chloroanisoles and chlorophenols in cork matrices was proposed. This methodology was applied with the aim of checking the efficiency of several washing treatments to remove the target analytes in naturally contaminated cork samples.Finally, different procedures have been developed for the analysis of wine samples. On one hand, chlorophenols were quantified by employing a SPME method. On the other hand, a reliable SPE method coupled to large volume injection was proposed for the determination of both 2,4,6-trichloroanisole and 2,4,6-tribromoanisole.

The object of the diploma thesis is a preparation of fundamental bases for realization aerofoils of the replica of the biplane aircraft BH534 Avia. The preambule of the work balances replica against the real historic aircraft. As next the basic aerodynamics characteristics, construction of aerofoils and strenght calculation of the aerofoils are described.

The topic of the thesis is a conceptual design of a roadable aircraft. The comparison of existing concepts is made, as well as description of proposed solution, aircraft mass analysis, basic aerostatic calculations, flight and gust envelope calculation and a design of truss construction of the fuselage. The CS-VLA, alternatively ELSA-K, has been used as a certification base. The compliance to this certification specification is one of the goals of this thesis.

<p dir="ltr">Methodologies for optimizing UAVs' control for varied environmental conditions have become crucial in the recent development for UAV control sector, yet they are lacking. This research focuses on the dynamism of the Gazebo simulator and PX4 Autopilot flight controller, frequently referenced in academic sectors for their versatility in generating close-to-reality digital environments. This thesis proposed an integrated simulation system that ensures realistic wind and gust interactions in the digital world and efficient data extraction by employing an industrial standard control communication protocol called MAVLink with the also the industry standard ground control software QGroundControl, using real and historical weather information from NOAA database. This study also looks into the potential of reinforcement learning, namely the DDPG algorithm, in determining optimal UAV safety distance, trajectory prediction, and mission planning under wind disruption. The overall goal is to enhance UAV stability and safety in various wind-disturbed conditions. Mainly focusing on minimizing potential collision risks in areas such as streets, valleys, tunnels, or really anywhere has winds and obstacles. The ROS network further enhanced these components, streamlining UAV response analysis in simulated conditions. This research presents a machine-learning approach to UAV flight safety and efficiency in dynamic environments by synthesizing an integrated simulation system with reinforcement learning. And the results model has a high accuracy, reaching 91%, 92%, and 97% accuracy on average in prediction of maximum shifting displacement, and left/right shifting displacement, when testing with real wind parameters from KLAF airport. </p>

L’aérodynamique latérale des véhicules automobiles suscite de nos jours de plus en plus d’intérêt de la part des constructeurs. L’automobiliste est en effet soumis quotidiennement à de forts courants d’air latéraux, que ce soit lors du dépassement d’un autre véhicule, ou alorsen passant dans un couloir de vent du à la topographie du terrain (passage devant un espace entre deux immeubles par exemple). Les efforts aérodynamiques mis en jeu dans ces situations peuvent provoquer des mouvements non désirés du véhicule, pouvant avoir des conséquences dramatiques si le conducteur se laisse surprendre. Des études expérimentales reproduisant les effets d’un dérapage dynamique ont mis en évidence des phénomènes transitoires importants mettant à défaut les modèles stationnaires généralement pratiqués par les constructeurs pour qualifier le comportement de leurs véhicules en présence de dérapage. Les mécanismes responsables de ces phénomènes transitoires sont encore mal connus de la communauté scientifique. Ce travail propose d’approfondir ce sujet au travers de l’étude de l’aérodynamique d’un véhicule terrestre fixe soumis à un vent longitudinal et à une rafale de vent latéral. Le but principal est d’identifier les structures tourbillonnaires au moyen de mesures PIV et de calculs numériques des champs de vitesse autour d’une maquette automobile et de les corréler aux efforts aérodynamiques. Un accord entre l’ISAT, composante de l’Université de Bourgogne, et l’Institut Supérieurde l’Aéronautique et de l’Espace (ISAE) de Toulouse a permis de mener l’étude avec les ressources de cet établissement. Le moyen d’essai principal, créé par l’ISAE, est le banc« rafale latérale », constitué d’une soufflerie principale et d’une soufflerie secondaire, dont la sortie à volet déferlants (« Mexican Wave ») est inspirée de l’approche proposée par Ryan et Dominy (2000). L’analyse expérimentale a été effectuée à l’aide de la PIV résolue en temps et stéréoscopique, et d’une balance dard instationnaire à cinq composantes. Un banc« numérique » identique a été constitué à l’aide du logiciel FLUENT©, pour des calculs 3D. De plus, un modèle 2D annexe, basé sur la méthode « meshless », a été développé pour de futures investigations, en raison de sa robustesse pour des problèmes à fortes discontinuités et sa bonne adaptabilité aux problèmes avec frontières mobiles.Une première phase de ce travail a consisté en la mise au point des bancs expérimental et numérique, avec génération d’un champ de dérapage homogène, de 21° dans la zone de mesure. L’évolution du dérapage en chaque point respecte bien la forme d’un créneau imposé par la rafale. Pour l’analyse des efforts, deux géométries de maquette ont été étudiées, à savoir un corps de Windsor à culot droit générant, pour un écoulement longitudinal, des structures de sillage bidimensionnelles, et son homologue à culot incliné de 25°, générant des tourbillons « cigare ». Des pics d’efforts ont été observés à l’arrivée de la rafale, tout comme la littérature le prédit. Pour ce qui est du coefficient du moment de lacet, les sursauts sont de 29 % et 19 % respectivement pour la maquette à culot droit et celle à culot incliné, par rapport aux valeurs stationnaires. Concernant le coefficient de force de dérive, ils sont de 10 % et 14 %, respectivement. Lors de nos essais, ces efforts se sont établis après 5.5 longueurs de maquette. Afin d’expliquer la différence de comportement entre les deux maquettes en termes d’efforts, l’évolution temporelle des tourbillons nommés, dans ce mémoire, ΓA, ΓB, ΓC et Γ1 à été discutée. Il en est ressorti une forte corrélation entre la circulation du tourbillon ΓA, le plusénergétique, naissant à l’avant du flanc sous le vent de la maquette, et les efforts latéraux, de sorte que ce tourbillon serait le meilleur témoin des phénomènes instationnaires mis en jeu dans l’étude de l’effet du vent latéral. [...] / The automotive manufacturers are nowadays more and more interested in crosswind aerodynamics. Indeed, the driver is subjected every day to strong side air flows, for example when overtaking another vehicle or when passing through a lateral wind wall, generated by terrain topography (as in the case of the passage near the empty space between two buildings).The aerodynamic efforts generated in these situations can lead to undesired lateral deviations,which can be dramatic if the driver is surprised. Different experimental studies, reproducing the effects of a dynamic yaw angle, pointed out the issues of the steady methods, commonly used to qualify the vehicle crosswind behaviour. Little is still known about the physics behind these unsteady phenomena. This is the main topic of this work, by studying the aerodynamics of a fixed vehicle subjected to both a longitudinal flow and a side wind gust. The goal is the identification of the near-vehicle vortex structures, by means of PIV measurements and CFD calculations, and their correlation with the evolution of the efforts. An agreement between the ISAT, a department of the University of Burgundy, and the ISAE of Toulouse, permitted to carry out this research with the resources of the latter laboratory. The work focuses on the use of the “rafale latérale” (side gust) test bench, made up with a main wind tunnel connected with an auxiliary one by means of a shutter system,whose opening is held by a “Mexican Wave” law. This approach is inspired by the work of Dominy and Ryan (2000). The experimental analysis was carried out by means of Time-Resolved and stereoscopic PIV, and by a five components unsteady balance as well. Anidentical test bench was numerically reproduced with the 3D CFD software FLUENT©.Moreover, an additional 2D CFD model, based on the meshless method, has been developed for future studies. This kind of approximation method has been chosen for its robustness innon-continuous problems and because of its adaptability when moving boundaries are needed.The first phase of this work consisted on wind tunnels set-up, both for the real test bench and for the CFD model. The yaw angle field is homogeneous, 21° in the measurement region. The yaw angle evolution, at given point, respects the step wise behaviour, imposed by the gust passage. As far as the efforts are concerned, two versions of the Windsor body car model were studied, that is a squareback geometry, generating, for longitudinal flows, 2D wakestructures, and a fastback geometry (rear window inclined by 25°), producing cone-liketrailing vortices. Force overshoots were seen after the gust arrival, as seen in literature. In particular, the yaw moment coefficient overshoots are 29% and 19% higher than the steady yaw angle tests, for the squareback and the fastback geometries, respectively. If the side forceis concerned, the entities of these overshoots are 10% and 14%, respectively. Our testspointed out that efforts establish after the vehicle has driven 5.5 times its length in thecrosswind. In order to explain the different behaviour of the two geometries, it is discussed about the unsteady evolution of the vortices called, in this report, ΓA, ΓB, ΓC et Γ1. A strong correlation between the side efforts and the circulation of the most energetic vortex, ΓA,having its origin in the front leeward side of the vehicle. The ΓA vortex is so the best index for the study of the crosswind unsteady phenomena. The coupled analysis between vortex structures and efforts confirmed the presence of a higher side force for the squareback geometry. The inverted effect has been observed for the yaw moment

A handling quality investigation was performed on the swept gull-wing configuration. The swept gull-wing configuration is tailless and has a wing with a transition in the sweep and dihedral angle. An example of this type of aircraft is the Exulans. This aircraft is currently under development at the University of Pretoria. The handling quality study was focussed on pitch axis dynamics. The Exulans is a research testbed that will be used to investigate the swept gull-wing configuration and its special controls by means of full-scale flight testing. Variable wing sweep, twisting elevons and winglets will be investigated as means of control. These control devices are configured in such a way as to have minimum impact on the performance of the aircraft. The handling qualities of the swept gull-wing configuration have to be acceptable while using these different control strategies. The study was launched to investigate whether a gull-wing configuration aircraft will have satisfactory handling qualities at CG positions associated with the most favourable aerodynamic performance. There is an aerodynamic performance gain in designing an aircraft so that the CG falls on the so-called `E-point'. The E-point is the centre of pressure for an elliptical circulation distribution. An elliptical circulation distribution is associated with the highest Oswald efficiency for an aircraft. Time domain simulation techniques and frequency domain analysis techniques were used to analyse the handling qualities of the gull-wing configuration. The C-star criterion was used to analyse handling qualities with time domain simulation data as input. Comparative time domain simulations were performed between the Exulans and other aircraft to compare handling qualities. Eigenvalue analysis was used together with the thumbprint criterion to investigate inherent gull-wing airframe dynamics. The Shomber-Gertsen and Military Specification 8785 criteria were also used for the same purpose. The Neal-Smith method was used to investigate the effect of control authority on handling qualities and the effect of a pilot. The Monnich and Dalldorff criterion was used to evaluate gust handling qualities. An analysis chart by Fremaux and Vairo was used to evaluate the tumbling susceptibility of the gull-wing configuration. The pitch handling quality investigation shows sufficient promise that the swept gull-wing configuration will have acceptable handling qualities with the CG placed at positions associated with optimised aerodynamic performance. Analysis showed that the swept gull-wing configuration is potentially prone to tumbling. With low static margins, the configuration should exhibit improved handling qualities in gusty conditions when compared to existing tailless aircraft. It is recommended that a lateral handling quality study be performed before full scale flight testing commences on the Exulans. In addition, the possibility of wingtip stall must be investigated for the case of the swept gull-wing configuration. / Dissertation (MEng)--University of Pretoria, 2008. / Mechanical and Aeronautical Engineering / unrestricted