Cette thèse concerne l'étude de l'interaction air-mer, due aux échanges de mouvements, avec un modèle idéalisé mais consistant. Les études sont réalisées à partir d'un modèle shallow-water bicouches (une pour l'océan et une pour l'atmosphère), avec une fine résolution spatiale et temporelle. L'interaction est uniquement due à la friction de surface entre les deux couches.Elle est implémentée par une loi de friction quadratique. La force appliquée à l'océan est calculée en utilisant la différence de vitesse entre les vents et les courants. Pour la force appliquée à l'atmosphère on distingue deux cas l'interaction ``1way'' et ``2way''. Pour la première, la friction appliquée à l'atmosphère néglige la dynamique de l'océan; elle est calculée en utilisant uniquement les vents. Pour l'interaction ``2W'', la friction appliquée à l'atmosphère est l'opposée de celle appliquée à l'océan.Trois configurations idéalisées sont explorées ici.La première configuration explique la génération d'une instabilité barotrope dans l'océan due à la force de friction quadratique et la dissipation visqueuse horizontale de l'atmosphère. Dans le cas 1W le cisaillement entraîne une instabilité barotrope dans l'océan. Dans le cas 2W, l'instabilité est amplifiée en amplitude et en dimension et est transférée à l'atmosphère. L'échelle principale de cette instabilité correspond à celle du rayon de Rossby dans l'océan. Elle est uniquement visible dans les modèles numériques, lorsque la dynamique est résolue à cette échelle à la fois dans l'océan mais aussi dans l'atmosphère.Dans la deuxième configuration, des expériences pour différentes valeurs du coefficient de traînée de surface sont réalisées. Le forçage diffère de la première configuration, et permet d'avoir une dynamique turbulente dans l'océan et l'atmosphère. L'énergie perdue par l'atmosphère et gagnée par l'océan par cisaillement à l'interface sont déterminées et comparées aux estimations basées sur les vitesses moyennes. La corrélations entre la vorticité océanique et atmosphérique est déterminée à l'échelle synoptique et méso-échelle de l'atmosphère. L'océan a un rôle passif, et absorbe l'énergie cinétique à quasiment tout les instants et tous les lieux. Les résultats différent des études réalisées à l'échelle du bassin. De par les faibles vitesses de l'océan, le transfert d'énergie dépend que faiblement des courants. La dynamique de l'océan laisse cependant son empreinte dans la dynamique de l'atmosphère conduisant à un état `quenched disorder' du système océan-atmosphère, pour le plus fort coefficient de friction utilisé.La dernière configuration, considère l'échange de mouvements entre l'océan et l'atmosphère autour d'une île circulaire. Dans les simulations actuelles de la dynamique océanique, le champs du forçage atmosphérique est généralement trop grossier pour inclure la présence de petites îles (<100km). Dans les calculs présentés ici, l'île est représenté dans la couche atmosphérique par un coefficient de traînée cent fois plus fort au dessus de l'île que l'océan. Cela engendre de la vorticité dans l'atmosphère , autour et près du sillage de l'île. L'influence de la vorticité atmosphérique sur la vorticité de l'océan, l'upwelling, la turbulence et le transfert d'énergieest considéré en utilisant des simulations couplées océan-atmosphère.Les résultats sont comparés avec des simulations ayant un forçage atmosphérique constant dans le temps et l'espace (pas de sillage) et des simulations "1W" (pour lesquelles les courants n'ont pas d'influence sur l'atmosphère).Les résultats des simulations sont en accords avec les travaux et les observations précédemment réalisés, et confirment que le sillage atmosphérique est le principal processus générant des tourbillons océanique dans le lit de l'île. Il est aussi montré que la vorticité est injectée directement par le rotationel du vent, mais aussi par la force du vent perpendiculaireau gradient d'épaisseur de la couche de surface océanique. / This thesis considers air-sea interaction, due to momentum exchange, in an idealized but consistent model. Two superposed one-layer fine-resolution shallow-water models are numerically integrated. The upper layer represents the atmosphere and the lower layer the ocean. The interaction is only due to the shear between the two layers. The shear applied to the ocean is calculated using the velocity difference between the ocean and the atmosphere.The frictional force between the two-layers is implemented using the quadratic drag law. Three idealized configurations are explored.First, a new mechanism that induces barotropic instability in the ocean is discussed. It is due to air-sea interaction with a quadratic drag law and horizontal viscous dissipation in the atmosphere. I show that the instability spreads to the atmosphere. The preferred spatial scale of the instability is that of the oceanic baroclinic Rossby radius of deformation.It can only be represented in numerical models, when the dynamics at this scale is resolved in the atmosphere and the ocean.In one-way interaction the shear applied to the atmosphere neglectsthe ocean dynamics, it is calculated using the atmospheric wind, only. In two-way interaction it is opposite to the shear applied to the ocean.In the one-way interaction the atmospheric shear leads to a barotropic instability in the ocean. The instability in the ocean is amplified, in amplitude and scale, in two-way interaction and also triggers an instability in the atmosphere.Second, the air-sea interaction at the atmospheric synoptic and mesoscale due to momentum transfer, only, is considered. Experiments with different values of the surface friction drag coefficient are performed, with a different atmospheric forcing from the first configuration, that leads to a turbulent dynamics in the atmosphere and the ocean. The actual energy loss of the atmosphere and the energy gain by the ocean, due to the inter-facial shear,is determined and compared to the estimates based on average speeds.The correlation between the vorticity in the atmosphere and the ocean is determined. Results differ from previous investigations where the exchange of momentum was considered at basin scale. It is shown that the ocean has a passive role, absorbing kinetic energy at nearly all times and locations.Due to the feeble velocities in the ocean, the energy transfer depends only weakly on the ocean velocity. The ocean dynamics leaves nevertheless its imprint in the atmospheric dynamics leading to a quenched disordered state of the atmosphere-ocean system, for the highest value of the friction coefficient considered. This finding questions the ergodic hypothesis, which is at the basis of a large number of experimental, observational and numericalresults in ocean, atmosphere and climate dynamics.The last configuration considers the air-sea interaction, due to momentum exchange, around a circular island. In todays simulations of the ocean dynamics, the atmospheric forcing fields are usually too coarse to include the presence of smaller islands (typically $<$ 100km).In the calculations presented here, the island is represented in the atmospheric layer by a hundred fold increased drag coefficient above the island as compared to the ocean. It leads to an increased atmospheric vorticity in the vicinity and in the wake of the island. The influence of the atmospheric vorticity on the ocean vorticity, upwelling, turbulence and energy transfer is considered by performing fully coupled simulations of the atmosphere-oceandynamics. The results are compared to simulations with a constant, in space and time, atmospheric forcing (no wake) and simulations with one-waycoupling only (where the ocean velocity has no influence on the atmosphere).Results of our simulations agree with previous published work and observations, and confirm that the wind-wake is the main process leading to mesoscale oceanic eddies in the lee of an island.

Esta tese apresenta os resultados da utilização de superfícies com microcanais como método de controle passivo de escoamento visando à redução do arrasto turbulento. Obtém-se essa redução pelo aumento da anisotropia das tensões de Reynolds junto à parede, situação em que o estado da turbulência se torna localmente axissimétrico e a uma componente. Utilizam-se as equações de Navier-Stokes para formular os escoamentos e o modelo de transporte de Tensões de Reynolds para computar as quantidades turbulentas. Aproximam-se essas equações pelo Método dos Volumes Finitos e a solução numérica é computada com o solucionador Star-CCM+ v. 8.06. Propõe-se um modelo de predição de redução de arrasto para uma placa plana com microcanais de seção retangular e dimensões geométricas variáveis, aplicando a formulação e o método numérico para calcular a anisotropia das tensões de Reynolds, o estado da turbulência e a redução de arrasto relativamente a uma placa de superfície lisa e de mesma área molhada. No capítulo de análise e discussão emprega-se o triângulo de Lumley-Pope para determinar o estado da turbulência e a trajetória de retorno à isotropia do escoamento, após verificar a incerteza numérica e validar o resultado com o modelo de predição e o da teoria da placa plana. Conduzem-se as análises quantitativas examinando as tensões de cisalhamento, as tensões de Reynolds e a morfologia do escoamento em pontos do interior e em superfícies lisas e adjacentes aos microcanais. Conclui-se apresentando uma visão geral dos resultados e propondo alternativas de desdobramento e continuidade deste trabalho. / The potential reduction of turbulent drag is investigated for flows over a flat plate with streamwise aligned microgrooves. For this purpose, the connection between the anisotropy of the Reynolds stresses and drag reduction effect is presented, and a model is developed in order to estimate the drag reduction potential according to flow and geometrical settings. The Navier-Stokes transport equations particularized for incompressible flows are used to describe the fluid motion, and the turbulence quantities are evaluated using the linear pressure-strain Reynolds stress transport model. The quantities are estimated using the Finite-Volume Method, which is applied to a set of grids with different refinement levels and groove topologies. After validating the numerical results against the predictions of the proposed model, and the theoretical estimates available in the literature, the author discusses the drag reducing effect by examining the state of turbulence in the microgrooves, also providing an assessment on the anisotropy of the Reynolds Stresses inside, near and outside the grooves. In the final chapter, conclusions are drawn, and outlooks of possible extensions to this work are suggested.

This study involved experimental and equivalent computational investigations into the automobile-type 3―D flow physics of a diffuser bluff body in ground-effect and novel passive flow-control methods applied to the diffuser flow to enhance the diffuser’s aerodynamic performance. The bluff body used in this study is an Ahmed-like body employed in an inverted position with the slanted section together with the addition of side plates along both sides forming the ramped diffuser section. The first part of the study confirmed reported observations from previous studies that the downforce generated by the diffuser in proximity to a ground plane is influenced by the peak suction at the diffuser inlet and subsequent static pressure-recovery towards the diffuser exit. Also, when the bluff body ride height is gradually reduced from high to low, the diffuser flow as indicated by its force curve and surface flow features undergoes four distinct flow regimes (types A to D). The types A and B regimes are reasonably symmetrical, made up of two low-pressure core longitudinal vortices travelling along both sides of the diffuser length and they increase downforce and drag with reducing ride height. However, below the ride heights of the type B regime, types C and D regimes are asymmetrical because of the breakdown of one vortex; consequently a significant loss in downforce and drag occurs. The second part of the study involved the use ― near the diffuser exit ― of a convex bump on the diffuser ramp surface and an inverted wing between the diffuser side plates as passive flow control devices. The modification of the diffuser geometry with these devices employed individually or in combination, induced a second-stage pressure-drop and recovery near the diffuser exit. This behaviour was due to the radial pressure gradient induced on the diffuser flow by the suction surface ii curvature of the passive devices. As a result of this aerodynamic phenomenon, the diffuser generated across the flow regimes additional downforce, and a marginal increase in drag due to the profile drag induced by the devices.

L’écoulement de refroidissement, qui pénètre par les entrées d’air sous le capot des véhicules automobiles,est étudié à partir de trois approches complémentaires : les approches théorique, expérimentale et numérique. Ces trois approches s’appuient sur une maquette simplifiée à culot droit basée sur le corps de Ahmed et équipée d’un compartiment moteur. Les mesures expérimentales montrent que placer la sortie du compartiment moteur au culot de la maquette est plus favorable à une faible traînée de refroidissement qu’une sortie placée au niveau du soubassement. La contribution de la traînée de refroidissement dans la traînée totale peut ainsi varier de 2% à 24%. Les simulations numériques donnent elles accès au débit de refroidissement. Pour les configurations étudiées, les sorties au culot sont là encore les plus favorables puisqu’elles fournissent les débits les plus importants à travers le milieu poreux modélisant un échangeur aérothermique. Par ailleurs, la mise en place d’étanchéités de part et d’autre de l’échangeur améliore significativement le débit de refroidissement où une augmentation d’environ 45% est obtenue. La mise en place d’un modèle analytique permet de relier la traînée et le débit de refroidissement à partir d’une analogie entre les circuits électriques et les écoulements fluides. Il est alors possible de prévoir le sens d’évolution du débit de refroidissement, donc de la performance des échangeurs aérothermiques, à partir d’une modification géométrique interne au compartiment moteur. / The cooling airflow, which flows through the underhood of motor vehicles from the inlet sections, is studied by means of three complementary approaches: the theoretical, experimental and numerical approaches. The three approaches use a simplified geometry with a blunt rear end, based on the Ahmed body, and equipped with an engine compartment. The experimental measurements show that locating the outlet section of the engine compartment at the base of the geometry favors low cooling drag values compared to an outlet section located in the underbody. The variation of the cooling drag contribution in the total drag is between2% and 24%, as a function of the location of the outlet. As for the numerical simulations, they provide the cooling flow rates. For the studied configurations, rear end outlets are again the most favorable since they provide the highest flow rates through the porous media that simulates a heat exchanger. Besides, the implementation of sealing above and below the porous media significantly increases the cooling flow rate by45%. An analytical model, based on the analogy between electrical circuits and fluid flows, connects the aerodynamic drag with the cooling flow rate. It is then possible to predict the evolution trend of the cooling flow rate, hence the heat exchangers efficiency, from a geometrical modification inside the engine compartment.

Dans cette thèse, une formulation pour l’extraction du couple « champ lointain » d’un rotor d’hélicoptère en vol stationnaire est présentée. Cette formulation est dérivée de la méthode d’extraction de la traînée « champ lointain » d’un avion, basée sur les travaux de van der Vooren et Destarac [?, ?, ?]. Un outil développé à l’Onera à partir de cette théorie permet de donner une analyse complète de la traînée aérodynamique d’un avion. Il est basé sur l’analyse physique et locale de l’écoulement calculé autour de l’aéronef, et décompose la traînée totale, aussi appelée traînée mécanique, en composantes physiques. Ces composantes physiques peuvent être définies comme suit : 1) la traînée d’onde, 2) la traînée visqueuse, 3) la traînée induite. L’adaptation de la méthode d’extraction de la traînée d’un avion à un rotor en vol stationnaire nécessite l’utilisation du couple rotor à la place de la traînée de l’avion, ce qui donne la décomposition suivante : 1) le couple d’onde, 2) le couple visqueux, 3) le couple induit. Les simulations de rotor diffèrent de celles de l’avion dans la mesure où les équations d’Euler (ou RANS) ne sont pas écrites dans le même repère de référence : les simulations d’avion utilisent généralement une formulation en vitesse relative tandis que les simulations d’un rotor d’hélicoptère utilisent la vitesse absolue projetée dans le repère relatif. Cette différence conduit à deux formulations différentes des équations de l’écoulement, et nécessairement deux formulations différentes de l’extraction de la traînée ou du couple. Ce changement de repère implique aussi des changements dans les quantités thermodynamiques utilisées, en particulier l’utilisation de la rothalpie à la place de l’enthalpie d’arrêt pour déterminer le couple dû aux phénomènes irréversibles. Une application de cette méthode est présentée sur un rotor quadripale créé pour cette étude et montre comment cette nouvelle approche peut améliorer la précision de l’extraction des performances d’un rotor à partir de résultat issu de la simulation numérique. / In this thesis, a formulation for “far-field” torque extraction in the case of a hovering rotor is presented. This formulation is derived from an aircraft “far-field” drag extraction method, based on van der Vooren and Destarac’s works [?, ?, ?]. A tool was previously developed at Onera to give an aerodynamic comprehensive analysis of aircraft drag, based on physical and local analysis of the computed flow field surrounding the aircraft. It decomposes the total drag, also called mechanical drag, into its physical components. These physical components can be defined as : 1) wave drag, 2) viscous drag, 3) induced drag. The adaptation of the method to a rotor in hover leads to consider rotor torque instead of aircraft drag, which gives the following decomposition : 1) wave torque, 2) viscous torque, 3) induced torque. Rotor simulations differ from aircraft ones inasmuch as the Euler (or RANS) equations are not written in the same reference frame : aircraft simulations use the relative velocity formulation while rotor simulations use the absolute velocity projected in the relative frame. This difference leads to two different formulations of the flow equations, and necessarily two different formulations of the drag or torque extraction. This change of reference frame also implies some changes in the thermodynamical quantities used, in particular the use of the rothalpy instead of the stagnation enthalpy to determine the torque due to irreversible phenomena. An application of this method is described on a four-bladed rotor created for this study and shows how this method can improve rotor performance extraction from numerical simulations.

A força propulsiva gerada durante o palmateio é resultado do somatório das forças de arrasto e de sustentação, sendo que a componente que atua na direção do movimento desejado é igual à força propulsiva efetiva. Essas forças podem ser estimadas a partir de equações hidrodinâmicas, porém essas equações não consideram todos os mecanismos que contribuem para a propulsão. Dessa forma, o objetivo geral do presente estudo foi comparar a força propulsiva efetiva calculada a partir das equações hidrodinâmicas e a força propulsiva efetiva medida durante o palmateio de sustentação (na posição vertical, de cabeça para cima) em cada fase do palmateio. Para isso, uma praticante de nado sincronizado realizou palmateio na posição vertical de cabeça para cima durante 15 segundos, enquanto que dados cinemáticos e cinéticos foram obtidos por viodeogrametria 3D e dinamometria respectivamente. A análise gráfica de Bland e Altman foi usada para comparar as forças propulsivas efetivas medida e calculada durante o palmateio. As forças propulsivas efetivas calculada e medida foram diferentes, sendo a medida maior que a calculada. Ainda, os resultados indicaram que o palmateio executado não foi simétrico, isto é, a orientação e a força propulsiva entre a mão direita e a esquerda foram diferentes. Portanto, o achado do presente trabalho destaca a importância de mecanismos instáveis para a propulsão durante o palmateio, já que as forças estimadas por meio das equações hidrodinâmicas apresentaram resultados inferiores, sendo isso observado ao longo de todo o palmateio. / Propulsive force generated during sculling motion results from drag and lift propulsive forces, and the component acting in the direction of motion is the effective propulsive force. These forces may be calculated using hydrodynamic equations, but these equations do not consider all mechanisms that contribute to the propulsion. Thus, the main purpose of this study was to compare the calculated effective propulsive force using the hydrodynamic equations and the measured effective propulsive force during a support sculling motion (vertical position with the head above the water‟s surface) in each phase of sculling. For this, a practitioner of synchronized swimming performed sculling motion in a vertical position with the head above the water‟s surface during 15 seconds, while kinematic and kinetic data were obtained by 3D videogrammetry and dynamometry respectively. Graphical techniques from Bland and Altman were used to compare the measured effective propulsive force and calculated effective propulsive force during sculling motion. The calculated effective propulsive force and the measured effective propulsive force were different, the measured being greater than the calculated. Moreover, the results indicated sculling motion performed was not symmetric, that is, the orientation and propulsive forces between the right and left hands were different. Therefore, the result of this study highlights the importance of the unsteady mechanisms for the propulsion during sculling motion, because the calculated forces using the hydrodynamic equations presented low values throughout the sculling motion.

O presente trabalho apresenta um estudo numérico dos efeitos da aplicação de geometrias geradoras de vórtices, com intuito de controlar passivamente a camada limite, em um perfil aerodinâmico que integra a asa traseira de multi elementos de um veículo de Fórmula SAE. As equações de Navier-Stokes com médias de Reynolds foram resolvidas utilizando o modelo k-ω SST (Shear Stress Transport) para o problema de fechamento da turbulência. Uma metodologia numérica padrão foi definida e utilizada nos diferentes casos analisados. Domínio de cálculo, malha, condições de contorno e critério de convergência foram escolhidos com base em norma SAE para análise numérica de escoamento externo em veículos terrestres. As camadas de volumes prismáticos próximos as superfícies com não-deslizamento foram dimensionadas de forma a resultar em um tratamento de parede adequado ao modelo de turbulência aplicado. O método GCI (Grid Convergence Index) foi utilizado para avaliar a qualidade da malha. Com o intuito de reduzir o custo computacional nos testes com diferentes configurações de geradores de vórtices, apenas parte de interesse do domínio de cálculo foi resolvido, impondo perfis de velocidade, energia cinética da turbulência e dissipação específica em sua entrada. Estas condições foram importadas da simulação com domínio completo resolvida Para verificar a correta captação dos principais efeitos físicos envolvidos, comparações com resultados experimentais foram feitas para 2 casos com escoamentos representativos: o corpo de Ahmed e um perfil aerodinâmico com geradores de vórtices. Além disso, as diferenças entre resolver o domínio completo ou parcial foram estudadas em outro comparativo com resultados experimentais. Concluiu-se que a metodologia numérica foi capaz de obter os coeficientes aerodinâmicos, e suas tendências frente a mudanças de geometria, nos casos estudados. Resolver parcialmente o domínio, impondo perfis em sua entrada, acarretou em diferença nos coeficientes obtidos na ordem de 2% para o coeficiente de sustentação e 7% para o coeficiente de arrasto. O controle passivo via geradores de vórtices foi eficaz em atrasar a separação da camada limite no flap do veículo de Fórmula SAE, as melhoras nos coeficientes de arrasto e sustentação foram da ordem de 7% e 0,3%, respectivamente. / The present work is a numerical study of the effects of the application of vortex generating geometries, in order to passively control the boundary layer, in an aerodynamic profile that integrates a multi-element rear wing of a Formula SAE vehicle. The Reynolds Averaged Navier-Stokes equations were solved using the k-ω Shear Stress Transport model for the turbulence closure problem. A standard numerical methodology was defined and used in the different cases analyzed. Computational domain, mesh, boundary conditions and convergence criteria were chosen based on SAE standard for numerical analysis of external flow in land vehicles. The layers of prismatic volumes near the non-slip surfaces were dimensioned to result in a wall treatment suitable to the applied turbulence model. The Grid Convergence Index (GCI) method was applied to evaluate the mesh quality. In order to reduce the computational cost in tests with different vortex generators configurations, only the part of interest of the calculation domain was solved, imposing velocity, turbulent kinetic energy and specific dissipation profiles on its inlet These conditions were imported from the full domain simulation already solved. To verify the correct capture of the main physical effects involved, comparisons with experimental results were made for 2 cases with representative flows: the Ahmed body and an aerodynamic profile with vortex generators. In addition, the differences between solving the complete or partial domain were studied in another comparative with experimental results. It was concluded that the numerical methodology was able to obtain the aerodynamic coefficients, and their tendencies against changes of geometry, in the cases studied. Partially solving the domain, imposing profiles at its entrance, resulted in a difference in the coefficients obtained in the order of 2% for the lift coefficient and 7% for the drag coefficient. The passive control via vortex generators was effective in delaying the separation of the boundary layer on the flap of the Formula SAE vehicle, the improvements in drag and lift coefficients were of the order of 7% and 0,3%, respectively.

Esta tese apresenta os resultados da utilização de superfícies com microcanais como método de controle passivo de escoamento visando à redução do arrasto turbulento. Obtém-se essa redução pelo aumento da anisotropia das tensões de Reynolds junto à parede, situação em que o estado da turbulência se torna localmente axissimétrico e a uma componente. Utilizam-se as equações de Navier-Stokes para formular os escoamentos e o modelo de transporte de Tensões de Reynolds para computar as quantidades turbulentas. Aproximam-se essas equações pelo Método dos Volumes Finitos e a solução numérica é computada com o solucionador Star-CCM+ v. 8.06. Propõe-se um modelo de predição de redução de arrasto para uma placa plana com microcanais de seção retangular e dimensões geométricas variáveis, aplicando a formulação e o método numérico para calcular a anisotropia das tensões de Reynolds, o estado da turbulência e a redução de arrasto relativamente a uma placa de superfície lisa e de mesma área molhada. No capítulo de análise e discussão emprega-se o triângulo de Lumley-Pope para determinar o estado da turbulência e a trajetória de retorno à isotropia do escoamento, após verificar a incerteza numérica e validar o resultado com o modelo de predição e o da teoria da placa plana. Conduzem-se as análises quantitativas examinando as tensões de cisalhamento, as tensões de Reynolds e a morfologia do escoamento em pontos do interior e em superfícies lisas e adjacentes aos microcanais. Conclui-se apresentando uma visão geral dos resultados e propondo alternativas de desdobramento e continuidade deste trabalho. / The potential reduction of turbulent drag is investigated for flows over a flat plate with streamwise aligned microgrooves. For this purpose, the connection between the anisotropy of the Reynolds stresses and drag reduction effect is presented, and a model is developed in order to estimate the drag reduction potential according to flow and geometrical settings. The Navier-Stokes transport equations particularized for incompressible flows are used to describe the fluid motion, and the turbulence quantities are evaluated using the linear pressure-strain Reynolds stress transport model. The quantities are estimated using the Finite-Volume Method, which is applied to a set of grids with different refinement levels and groove topologies. After validating the numerical results against the predictions of the proposed model, and the theoretical estimates available in the literature, the author discusses the drag reducing effect by examining the state of turbulence in the microgrooves, also providing an assessment on the anisotropy of the Reynolds Stresses inside, near and outside the grooves. In the final chapter, conclusions are drawn, and outlooks of possible extensions to this work are suggested.

A força propulsiva gerada durante o palmateio é resultado do somatório das forças de arrasto e de sustentação, sendo que a componente que atua na direção do movimento desejado é igual à força propulsiva efetiva. Essas forças podem ser estimadas a partir de equações hidrodinâmicas, porém essas equações não consideram todos os mecanismos que contribuem para a propulsão. Dessa forma, o objetivo geral do presente estudo foi comparar a força propulsiva efetiva calculada a partir das equações hidrodinâmicas e a força propulsiva efetiva medida durante o palmateio de sustentação (na posição vertical, de cabeça para cima) em cada fase do palmateio. Para isso, uma praticante de nado sincronizado realizou palmateio na posição vertical de cabeça para cima durante 15 segundos, enquanto que dados cinemáticos e cinéticos foram obtidos por viodeogrametria 3D e dinamometria respectivamente. A análise gráfica de Bland e Altman foi usada para comparar as forças propulsivas efetivas medida e calculada durante o palmateio. As forças propulsivas efetivas calculada e medida foram diferentes, sendo a medida maior que a calculada. Ainda, os resultados indicaram que o palmateio executado não foi simétrico, isto é, a orientação e a força propulsiva entre a mão direita e a esquerda foram diferentes. Portanto, o achado do presente trabalho destaca a importância de mecanismos instáveis para a propulsão durante o palmateio, já que as forças estimadas por meio das equações hidrodinâmicas apresentaram resultados inferiores, sendo isso observado ao longo de todo o palmateio. / Propulsive force generated during sculling motion results from drag and lift propulsive forces, and the component acting in the direction of motion is the effective propulsive force. These forces may be calculated using hydrodynamic equations, but these equations do not consider all mechanisms that contribute to the propulsion. Thus, the main purpose of this study was to compare the calculated effective propulsive force using the hydrodynamic equations and the measured effective propulsive force during a support sculling motion (vertical position with the head above the water‟s surface) in each phase of sculling. For this, a practitioner of synchronized swimming performed sculling motion in a vertical position with the head above the water‟s surface during 15 seconds, while kinematic and kinetic data were obtained by 3D videogrammetry and dynamometry respectively. Graphical techniques from Bland and Altman were used to compare the measured effective propulsive force and calculated effective propulsive force during sculling motion. The calculated effective propulsive force and the measured effective propulsive force were different, the measured being greater than the calculated. Moreover, the results indicated sculling motion performed was not symmetric, that is, the orientation and propulsive forces between the right and left hands were different. Therefore, the result of this study highlights the importance of the unsteady mechanisms for the propulsion during sculling motion, because the calculated forces using the hydrodynamic equations presented low values throughout the sculling motion.

Good estimation of aerodynamic coefficients is of fundamental importance in the design and development process of an aircraft. Generally, these parameters are obtained using analytical, numerical and experimental methods, which are sometimes either inaccurate or very expensive. The use of subscale aircraft is becoming increasingly common in the study and evaluation of new aircraft concepts. Flight testing results in an efficient solution for obtaining parameters that can define drag characteristics. This project presents a solution for achieving the drag aerodynamic model from the design and manufacturing of a micro engine thrust measuring system integrated on subscale aircraft. Strain gauge technology permits to identify the stresses that the engine forces cause to the aircraft internal structure by analysing the strain of several strategic zones of the engine mounting created for this purpose. Different structural support geometries have been presented and stress-analysed together with the design of the appropriate strain gauge model conguration in order to select and manufacture a system that represents a good compromise between all the requirements while ensuring the quality and accuracy of the data acquired. After calibration, installation and set-up, the system is ready for real in-flight measurements.