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This paper presents an analysis of sound pressure levels through theoretical modeling and experimental validation in a 1 kW small wind turbine. The models used in the theoretical analysis are BPM (Brooks, Pope, and Marcolini) and BM (Brooks and Marcolini), where wind turbine blades are divided in sections, and each section has its own contribution with respect to the total emitted sound pressure level. The noise propagation study and its experimental validation were accomplished within the requirements of the standard IEC 61400-11 Ed.3 and the standard NOM-081-SEMARNAT-1994. The comparative study of theoretical and experimental results showed that the BPM and BM methods have a maximum error of 5.5% corresponding to the rated wind speed of 10 m/s. However, at low wind speeds, the theoretical models fit well to experimental data, for example, in the range from 5 to 8 m/s. The experimental data showed that the rotor’s aerodynamic noise is more evident at low wind speed, because under these conditions, environmental noise is much less than wind turbine noise. Finally, to prevent possible negative effects on people’s health, there is a recommended minimum and suitable distance between small wind turbine installations and buildings.

Оцінка характеристик аеродинамічних поверхонь у трансзвуковому потоці повітря теоретичними методами залишається актуальною науковою проблемою, яку необхідно вирішувати при удосконаленні методів дослідження аеропружних характеристик надзвукових літаків та аерокосмічних систем на трансзвукових швидкостях польоту.Труднощі вирішення проблеми обумовлені необхідністю врахування впливу стиснення повітря на зміну характеристик аеродинамічних профілів надзвукових літаків у трансзвуковому діапазоні швидкостей польоту. У деяких працях вплив стиснення повітря на зміну характеристик аеродинамічних профілів враховується за допомогою різноманітних поправок. Але похибка оцінки коефіцієнту тиску місцевого надзвукового потоку на поверхні аеродинамічного профілю с урахуванням стиснення повітря за допомогою цих поправок може бути дуже великої навіть для інженерних наближених оцінок.Додаткові труднощі оцінювання характеристик аеродинамічних поверхонь надзвукових літаків на трансзвукових швидкостях польоту виникають при формуванні стрибків ущільнення на поверхні аеродинамічного профілю, вплив яких цими поправками не може бути визначений.У статті для оцінки характеристик аеродинамічних профілів надзвукових літаків на трансзвукових швидкостях польоту пропонується метод, який базується на сумісному аналізу рівнянь Бернуллі для стислого газу і закономірностей зміни параметрів надзвукового струму у течії Прандтля – Майера та дозволяє оцінювати величини зміни тиску місцевого надзвукового потоку на профілі аеродинамічної поверхні керування при виникненні трансзвукового флатеру з достатньої для інженерних оцінок точністю.З порівняння отриманих запропонованим методом величин зміни тиску місцевого надзвукового потоку на профілю аеродинамічної поверхні керування з результатами, отриманими під час льотних та лабораторних досліджень, зроблено висновок щодо можливості використання запропонованого методу для попередньої наближеної оцінки деяких характеристик трансзвукового флатеру аеродинамічних поверхонь керування надзвукових літаків та аерокосмічних систем., Estimation of aerodynamic surface characteristics in transonic airflow using theoretical methods remains an urgent scientific problem that needs to be addressed on the way of improvement of methods for investigating the aeroelastic characteristics of supersonic airplanes and aerospace systems at transonic flight speeds.Difficulties in solving the problem are due to the need to take into account the effect of air compression on the change in the characteristics of the aerodynamic profiles of supersonic airplanes in the transonic flight speed range. In some papers, the effect of air compression on changing the characteristics of the aerodynamic profiles is taken into account by various corrections. But the error in estimating the pressure coefficient of the local supersonic flow on the surface of an aerodynamic profile with the use of the air compression corrections can be very considerable, even for engineering approximate estimates.Additional difficulties in estimation of the characteristics of aerodynamic surfaces of supersonic airplanes at transonic flight speeds arise under formation of shock waves on the surface of an aerodynamic profile the impact of which cannot be determined by the abovementioned corrections.In the article, for estimation of the characteristics of aerodynamic profiles of supersonic airplanes at transonic flight speeds, the authors propose a method based on a joint analysis of the Bernoulli equations for compressed gas and the change patterns of the supersonic flow parameters of the Prandtl–Meyer expansion fan that make it possible to estimate, with sufficient engineering precision, the pressure change of a local supersonic flow on the aerodynamic control surface profile in case of transonic flutter.Comparing the values of changes in the pressure of the local supersonic flow on aerodynamic control surface profiles obtained by the proposed method with the results received during flight and laboratory studies, it is concluded that it is possible to use the proposed method for preliminary approximate estimation of some characteristics of transonic flutter of aerodynamic control surfaces of supersonic aircraft and aerospace systems.

The aerodynamic design of a rigid-flexible coupling profile is the decisive factor for the flow-field quality of a supersonic free jet wind tunnel nozzle, and its mechanic dynamic features are the key for engineering implementation of continuous Mach number regulations. To fulfill the requirements of a free jet inlet/engine compatibility test within a wide simulation envelop, both uniform flow-fields of continuous acceleration and deceleration are necessary. In this paper, the aerodynamic design methods of an expansion wall and machinery implementation plan for the half-flexible single jack nozzle were researched. The profile control in nozzle flexible plate design was studied with a rigid-flexible coupling method. Design and calculations were performed with the help of numerical simulation. The technique of axial free stretching of the flexible plate was used to improve the matching performance between the designed elasticity profile and the theoretical one, and the rigid-flexible coupling structure was calibrated by wind tunnel tests. Results indicate that the flexible plate aerodynamic design method used here is effective and feasible. Via rigid-flexible coupling design, the flexible plate agrees with the rigid body very well, and continuous Mach number changes can be achieved during the tests. The nozzle’s exit flow-field uniformity meets the requirements of China Military Standard (GJB).

Tema ovog rada biti će neuronske mreže. Prije svega, navest ću pod kojim su utjecajem i kako one nastale, koja im je bila svrha u doba njihova nastanka, a u koju su pak svrhu one korištene danas. Potom ću opisati postupak izrade vlastite neuronske mreže u programskom jeziku C#. Cilj ovog rada je izraditi vlastitu neuronsku mrežu koja će biti korištena u desktop aplikaciji kako bi napravila izračun aerodinamičkih profila. The topic of this thesis will be neural networks. First off, I plan to mention how were they invented, and what were the ideas that influenced their discovery, what was their purpose at the time of their invention, and what their purpose is today. After that, I will describe the process of creating my own neural network by using C# programming language. The goal of this thesis is to create a neural network which will be used in desktop application to calculate aerodynamic profiles.

Materials used in the development and construction of the blades are essential for the proper functioning of wind turbines. The challenges of engineers are related to the optimum combination of the following structural properties: optimum rigidity - specific gravity; lifetime to fatigue and flexibility; low cost of materials and processing to achieve the desired aerodynamic shape. The purpose of this paper is identification of risk areas of wind turbine blades and composite structural optimization of their structure in areas exposed to combined loading, using finite element analysis. Optimizing structural composites depending on risk areas is a difficult issue because it must take into account the aerodynamic profile, proper positioning of the center of gravity and dynamic and elastic center of blade so that during operation, will not develop the inertial masses to affect the functioning and integrity of the blades. In the first stage of the research, the blade structure with a length of 1.5 m and profile NACA 2412 was modeled from composite fiber reinforced polymer, with 7, 9, 11, 13, 15 layers of fiber glass fabric and mat with epoxy resin as matrix. Once static analysis, the risk areas where determined taking into account the maximum values of normal and tangential stresses. In the next stage, structural optimization and verification was performed, the state of stress and strain being compared to stress obtained initially. There were also determined the optimum package of composite taking into account the reduction of blade mass. It was found that increasing the number of layers in risk areas and their reduction to the blade tip leads to increasing resistance to static and dynamic loads. Orientation of layers can improve the static and dynamic behavior. The study aims to applying the finite element method in designing composites used in wind turbine blades structure, reducing the cost of production and improving the structure.

The world is counting on wind energy to provide a sustainable energy source. Wind is abundant, clean and renewable, instead of fossil reserves that are widely distributed in the five continents. For this reason, we have designed an aerogenerator, called ELISA, the rotor has a parabolic dish shape which can capture and convert more kinetic energy of the wind into mechanical energy, and the rotor is made of polyurethane resin reinforced with carbon nanotubes, which is lighter and has better mechanical properties, in consequence this allow to optimize the energy production of the aerogenerator., La energía eólica es la tecnología que el mundo está contando para proporcionar una fuente de energía sostenible. El viento es abundante, limpio y renovable, a diferencia de las reservas fósiles que se distribuyen ampliamente en los cinco continentes. Por este motivo, rediseñamos un aerogenerador, el cual hemos denominado ELISA, el rotor posee una forma de disco parabólico capaz de capturar y convertir más energía cinética del viento en energía mecánica, además que dicho rotor se ha desarrollado en base a una resina de poliuretano reforzada con nanotubos de carbono, la cual es más liviana y posee mejores propiedades mecánicas; en consecuencia, permitirá optimizar al máximo la producción energética del aerogenerador.

The world is counting on wind energy to provide a sustainable energy source. Wind is abundant, clean and renewable, instead of fossil reserves that are widely distributed in the five continents. For this reason, we have designed an aerogenerator, called ELISA, the rotor has a parabolic dish shape which can capture and convert more kinetic energy of the wind into mechanical energy, and the rotor is made of polyurethane resin reinforced with carbon nanotubes, which is lighter and has better mechanical properties, in consequence this allow to optimize the energy production of the aerogenerator., La energía eólica es la tecnología que el mundo está contando para proporcionar una fuente de energía sostenible. El viento es abundante, limpio y renovable, a diferencia de las reservas fósiles que se distribuyen ampliamente en los cinco continentes. Por este motivo, rediseñamos un aerogenerador, el cual hemos denominado ELISA, el rotor posee una forma de disco parabólico capaz de capturar y convertir más energía cinética del viento en energía mecánica, además que dicho rotor se ha desarrollado en base a una resina de poliuretano reforzada con nanotubos de carbono, la cual es más liviana y posee mejores propiedades mecánicas; en consecuencia, permitirá optimizar al máximo la producción energética del aerogenerador.

As a results of this State Program there were revealed many unknown materials up nowadays in the areas of wind energy exploitation. Wind energy exploitation: elaboration of the new (patented) constructive concept of vertical axis wind turbine (VAWT) with helical blades, which transform the kinetic energy of the air-masses into mechanical work, having as a basis the forces of interaction among the active elements of the rotor and the air fl ow, which attack it with a certain speed; the numerical simulation of the aerodynamic blades with NACA 0015-0021 profi le; wind tunnel testing of the aerodynamic sample of blades.

The results of experimental studies of the effect of relative curvature of the airfoils on the degreeof change in their characteristics in terms of additional pulse velocity in the boundary layer topsurface profile generated by a rotating cylinder. It was found that the growth profile of the greatercurvature of the lift coefficient in the linear region up to increase the lift coefficient by theapplication of flap - the flap

Volatilization of pesticides from crops in the field can be an important emission pathway. In a field experiment with characterization of meteorological conditions, the pesticides chlorpyrifos and fenpropimorph were sprayed onto a potato crop, after which concentrations in the air and on/in the plants were measured. Rates of volatilization were estimated with the aerodynamic profile (ADP), energy balance (EB), relaxed eddy accumulation (REA), and plume dispersion (PD) methods. The volatilization rates obtained with the ADP and EB methods were similar, while some rates obtained with the REA and PD methods in the initial period were lower. Cumulative volatilization of chlorpyrifos during daylight hours (ADP and EB methods) was estimated to be about 65% of the dosage. By far the majority of this volatilization occurred in the first few days. Competing processes at the plant surface had a considerable effect on the dissipation of fenpropimorph, so cumulative volatilization during daylight hours was estimated to be only 7% of the dosage. Plant surface residues were higher than would correspond with the volatilization rate, indicating that penetration into the leaves had occurred. © 2006 American Chemical Society.

International audience; For many years, the use of complex surfaces is becoming widespread with the development of manufacturing process. CAD model describes nominal shape of the part. Specifications are then defined by annotations directly in the 3D model. This work is illustrated by an application on a turbine blade of an aircraft engine. To impose the widest possible tolerances on the whole surface, it is necessary to have a multi-scale approach. The main datum reference frame is built on the setting up surfaces of the part. In the first level, all surfaces are located with regard to the main datum reference frame with a wide tolerance in order to avoid interference with other parts of the mechanism. In a second level, specifications on restricted areas complete local requirements with lower tolerances. In the third level, orientation specification on small mobile zone with small tolerance detects micro defects as tool traces for example. This presentation shows several positions, orientation and form specifications on 3D surfaces and on 2D curves. The new modifier "For orientation constraint only" of the ISO 5459: 2011 standard lets us define only the orientation with regard to a reference surface. The overlapping of many orientation specifications on restricted areas limits parts defects inside a large global tolerance zone. Specifications with common zone of two surfaces face to face control the thickness of the part which can be useful for strength or mass reasons. These specifications can be detailed with a variable tolerance zone that defines the tolerance of all points of surfaces. The ISO standard only treats the 2D case; this paper presents a solution to specify 3D surfaces with variable tolerance by a hypothesis of proportional variation following the curvilinear distance on curves created on 3D surfaces. This set of specifications constitutes a toolbox for designers based on only one type of specification which allows them to verify all requirements with a partition of only one cloud of points. The 3D complex surfaces are the interface between the part and the outside environment and often require similar functions. This study in a context of aeronautic industry can easily be extended to other mechanical domains.

V diplomskem delu je predstavljen razvoj lopatice vetrne turbine. Lopatica vetrne turbine je del rotorja vetrne turbine, ki vetru zaradi svoje oblike odvzema energijo, katero kasneje izkoriščamo kot električno energijo. Razviti je potrebno lopatico vetrne turbine, katera bo imela boljši izkoristek oz. bo proizvedla več moči kot njena predhodnica. Na začetku naloge so opisane glavne lastnosti in metode ter napotki za razvoj učinkovite lopatice vetrne turbine. V nadaljevanju je prikazan postopek izračuna in dimenzioniranja nove lopatice, ki se konča s primerjavo rezultatov obstoječe lopatice in nove lopatice. Na koncu je geometrija nove lopatice prikazana z modelom v programskem paketu SolidWorks. The diploma thesis presents the development of wind turbine blade. The wind turbine blade is a part of the rotor for wind turbine which exploits the wind energy due to its design that is later generated into the electricity. The wind turbine blade, having a better efficiency, namely one that will produce more power than its predecessor, needs to be developed. The main characteristics, methods and instructions how to develop an efficient wind turbine blade are described in the first part of the thesis. Furthermore, the method of calculation and dimensioning of the new blade is presented and concluded by a comparison of the results made between the existing and the new blade. In the last part of thesis, the geometry of new blade is demonstrated together with a model in the SolidWorks software package.

This work presents the coupling between two different formulations applied to flow simulation and analysis of wind rotors, integral and differential formulations. First, for the integral formulation is defined a control volume where the variables problem are defined, as well as the necessaries working hypothesis, then a proposed mathematical modeling is defined. Simulations through NACA airfoils, using Computational Dynamic Fluids, are performed in order to evaluate drag and lift coefficients, to be used in the integral formulation. The Navier-Stokes equations are solved in house and the Smagorinsky turbulence model with Van Driest damping function is retained. The computational code is implemented with structured cartesian mesh, where the airfoil is modeled using the Immersed Boundary Methodology. The results of simulation through a NACA0012 airfoil are shown for several attack angles and Re = 10000. Results of energetic efficiency are presented for a horizontal axis wind turbine using the integral formulation, where the coefficients are given by differential formulations. Este trabalho apresenta o acoplamento entre as duas formulações diferentes aplicadas à simulação do escoamento e análise de rotores eólicos, formulações integral e diferencial. Primeiramente para a formulação integral é definido um volume de controle onde as variáveis do problema são definidas, bem como as hipóteses simplificadoras necessárias, para então ser proposta uma modelagem matemática. Simulações do escoamento em aerofólios NACA, utilizando Dinâmica dos Fluidos Computacional, são realizadas a fim de determinar os coeficientes de arrasto e sustentação, os quais foram utilizados na formulação integral. As equações de Navier-Stokes são resolvidas em um código computacional e o modelo de turbulência de Smagorinsky com função de amortecimento de Van Driest é utilizado. O código computacional é implementado com uma malha cartesiana estruturada, e o aerofólio é modelado utilizando a Metodologia da Fronteira Imersa. Os resultados da simulação através de um aerofólio NACA0012 são mostrados para vários ângulos de ataque e Re = 10000. Os resultados de eficiência energética são apresentados para uma turbina eólica de eixo horizontal utilizando a formulação integral, onde os coeficientes são dados pelas formulações diferenciais. Mestre em Engenharia Mecânica

Основною особливістю мікролітальних безпілотних апаратів є політ на числах Рейнольдса близьким до критичних. Цей фактор істотно впливає на аеродинамічний вигляд апарату. У статті пропонується для підвищення аеродинамічних характеристик мікро БпЛА використовувати аеродинамічні профілі Кляйна-Фогельмана і проведена оцінка їх переваг в порівнянні з широко поширеними, для даного типу апаратів, профілями. The main feature of the unmanned microaircraft is a flight near-critical Reynolds numbers. This factor significantly affects on the aerodynamic shape. Depending from the aerodynamic configuration and destination of the microplane use S – shaped profile, and profiles with large curvature and small relative thickness, but they don’t provide an effective device for its intended purpose. It’s proposed to improve the aerodynamic characteristics of microaircraft by using Klein-Fogelman profiles. By assumption of developers this type of development profiles in its technological simplicity allow, in comparison with classical profiles to receive important aerodynamic qualities. Klein profiles Fogelman is a family-step profiles. Compared with classic profiles, which increase in thickness in order to increase the lift coefficient, are contributing to the growth profile drag, profile Kleine Fogelman can improve the value as of the lift coefficient as profile drag. This paradox is explained by the specific geometry of the profile of the class. The flow of air, flowing around this partly rigid, partly air profile creates lift. Since in the area of the vortex flow of air rubs against the air, the drag of the wing with the profile obtained significantly lower resistance of similar wing with a conventional profile. Thus, the aerodynamic efficiency of the wing with the Klein-Fogelman profile s lower. In the present study evaluated the benefits of beating Klein-Fogelman profiles over typical for this type of devices profiles. It was determined that the use of the device to create profiles microaircraft Klein-Fogelman, despite its simplicity, can significantly increase the profile aerodynamic efficiency, compared with the applicable profiles. Основной особенностью микролетательных беспилотных аппаратов является полет на околокритических числах Рейнольдса. Этот фактор существенно влияет на аэродинамический облик. В статье предлагается для повышения аэродинамических характеристик микро-БпЛА использовать профили Кляйна-Фогельмана и проведена оценка их преимуществ по сравнению с широко распространенными, для данного типа аппаратов, профилями.

The using of adaptive wing structures in modern aircraft is the one with effective solutions that improve takeoff and landing performance of the aircraft. Existing designs of adaptive wings are quite complicated, making them difficult to implement in small unmanned aircrafts. Knowledge of the laws and methods of changing the shape of the profile is an important and urgent topic of research in the design of adaptive wing. At the same time, the trend of development of unmanned vehicles requires a search for new technical solutions to realize the benefits of adaptive wing.One embodiment of the adaptive wing is a wing with variable camber. Changing the camber allows you to adjust the picture of the pressure distribution on the wing, and thus adjust the values of the aerodynamic forces and moments. This article suggests to introduce change profile curvature by mechanical deformation of the bottom surface.The aim of work is the evaluation of the character of changes of aerodynamic profile settings depending on the curvature of the bottom surface and the accuracy of its formation. Also analyzed the possibility of using adaptive wing of this type in the construction of small UAVs.As a result of the research was defined the optimal range of the relative concavity of the profile and value of the lift coefficient of variation in this case. Also, based on the assessment of the impact the accuracy of the formation of the aerodynamic profile of the wing, it was determined that having three break points of the bottom surface, we can obtain the range of variation of the lift coefficient close to the calculated theoretical value. This fact suggests that such an adaptive wing can be realized on small aircraft.Actual direction for further research, the lower profile with a deformable surface, it is possible to use it for lateral control planes., Применение адаптивного крыла в современных конструкциях самолета является одним с эффективных решений позволяющих улучшить взлетно-посадочные характеристики летательного аппарата. Существующие конструкции адаптивных крыл достаточно сложны, что затрудняет их реализацию в малоразмерных беспилотных летательных аппаратах. В статье предложен вариант реализации адаптивного крыла с механической деформацией нижней поверхности. Проведена оценка характера изменений аэродинамических параметров профиля в зависимости от кривизны нижней поверхности и точности ее формирования., Застосування адаптивного крила в сучасних конструкціях літака є одним з ефективних рішень, що даютє змогу поліпшити характеристики літального апарату на режимах зльоту та посадки. Існуючі конструкції адаптивних крил досить складні, що утрудняє їх реалізацію в малорозмірних безпілотних літальних апаратах. У статті запропонований варіант реалізації адаптивного крила з механічною деформацією нижньої поверхні. Проведено оцінку характеру змін аеродинамічних параметрів профілю в залежності від кривизни нижньої поверхні і точності її формування.

Застосування адаптивного крила в сучасних конструкціях літака є одним з ефективних рішень, що даютє змогу поліпшити характеристики літального апарату на режимах зльоту та посадки. Існуючі конструкції адаптивних крил досить складні, що утрудняє їх реалізацію в малорозмірних безпілотних літальних апаратах. У статті запропонований варіант реалізації адаптивного крила з механічною деформацією нижньої поверхні. Проведено оцінку характеру змін аеродинамічних параметрів профілю в залежності від кривизни нижньої поверхні і точності її формування. The using of adaptive wing structures in modern aircraft is the one with effective solutions that improve takeoff and landing performance of the aircraft. Existing designs of adaptive wings are quite complicated, making them difficult to implement in small unmanned aircrafts. Knowledge of the laws and methods of changing the shape of the profile is an important and urgent topic of research in the design of adaptive wing. At the same time, the trend of development of unmanned vehicles requires a search for new technical solutions to realize the benefits of adaptive wing. One embodiment of the adaptive wing is a wing with variable camber. Changing the camber allows you to adjust the picture of the pressure distribution on the wing, and thus adjust the values of the aerodynamic forces and moments. This article suggests to introduce change profile curvature by mechanical deformation of the bottom surface. The aim of work is the evaluation of the character of changes of aerodynamic profile settings depending on the curvature of the bottom surface and the accuracy of its formation. Also analyzed the possibility of using adaptive wing of this type in the construction of small UAVs. As a result of the research was defined the optimal range of the relative concavity of the profile and value of the lift coefficient of variation in this case. Also, based on the assessment of the impact the accuracy of the formation of the aerodynamic profile of the wing, it was determined that having three break points of the bottom surface, we can obtain the range of variation of the lift coefficient close to the calculated theoretical value. This fact suggests that such an adaptive wing can be realized on small aircraft. Actual direction for further research, the lower profile with a deformable surface, it is possible to use it for lateral control planes. Применение адаптивного крыла в современных конструкциях самолета является одним с эффективных решений позволяющих улучшить взлетно-посадочные характеристики летательного аппарата. Существующие конструкции адаптивных крыл достаточно сложны, что затрудняет их реализацию в малоразмерных беспилотных летательных аппаратах. В статье предложен вариант реализации адаптивного крыла с механической деформацией нижней поверхности. Проведена оценка характера изменений аэродинамических параметров профиля в зависимости от кривизны нижней поверхности и точности ее формирования.

The torsional deformation of aerodynamic profiles has to be considered with care because it induces a change in the angle of attack and therefore changes in the local densities of lift and drag forces. The improvement of the aerodynamic performances does require a good knowledge and control of the twist of the airfoil. A method currently developed by a lot of authors consists in inserting in the airfoil some actuators whose action tends to increase or reduce the ‘natural’ deformation of the structure. This method, named active control, is very effective but it has some limitations because it needs a level of energy which can be high. The method we propose to control the twist of the airfoil consists in modifying the internal elastic equilibrium of the structure. By joining or disjoining some walls inside the profile, it is possible to shift the shear center of the profile without any change of its external shape. So, these internal modifications induce variations of the torsional moment and therefore a variation of the twist angle. The process is no energy consuming. By means of a simple profile, simulations have been performed to show the theoretical potential of the proposed system. Three demonstrators have also been designed with increasing complexity to evaluate the feasibility of the ‘reactive’ control of the twist. The technique has been validated by the second demonstrator. Unfortunately, the third demonstrator, much more complex, has not shown the final demonstration., La déformation de torsion que subit un profil aérodynamique a une importance capitale car elle a une influence directe sur la valeur des incidences locales et donc sur la valeur locale des densités de portance et de traînée. L'amélioration des performances aérodynamiques passe donc par la connaissance et la maîtrise de ce vrillage. Cette thèse se propose d'y contribuer. Une des méthodes développées actuellement par de nombreux auteurs consiste à munir le profil d'actionneurs permettant de le déformer en torsion de manière à compenser tout ou partie, voire même contrer, la déformation « naturelle » de la structure. Cette méthode, dite de contrôle actif, est certes très efficace, mais elle présente des limitations car elle nécessite l'introduction d'une quantité d'énergie qui peut être importante. La méthode que nous proposons ici pour maîtriser le vrillage du profil consiste à modifier ses conditions d'équilibre interne. En solidarisant ou en désolidarisant des cloisons à l'intérieur du profil, il est possible de déplacer le centre de torsion des sections du profil sans modifier sa forme extérieure. Ces modifications internes induisent donc une modulation du moment de torsion et donc une modulation du vrillage. Ce processus ne demande que très peu d'énergie. A partir d'un profil simple, des simulations ont permis de montrer le potentiel théorique du système proposé. Trois démonstrateurs, de complexité croissante, ont également été réalisés pour évaluer les capacités du contrôle « réactif » de la torsion. La technique a été validée par la deuxième démonstration. Malheureusement, le troisième démonstrateur, beaucoup plus complexe, n'a pas permis, à l’heure actuelle, d'obtenir la validation finale.

Volatilization of pesticides from crops in the field can be an important emission pathway. In a field experiment with characterization of meteorological conditions, the pesticides chlorpyrifos and fenpropimorph were sprayed onto a potato crop, after which concentrations in the air and on/in the plants were measured. Rates of volatilization were estimated with the aerodynamic profile (ADP), energy balance (EB), relaxed eddy accumulation (REA), and plume dispersion (PD) methods. The volatilization rates obtained with the ADP and EB methods were similar, while some rates obtained with the REA and PD methods in the initial period were lower. Cumulative volatilization of chlorpyrifos during daylight hours (ADP and EB methods) was estimated to be about 65% of the dosage. By far the majority of this volatilization occurred in the first few days. Competing processes at the plant surface had a considerable effect on the dissipation of fenpropimorph, so cumulative volatilization during daylight hours was estimated to be only 7% of the dosage. Plant surface residues were higher than would correspond with the volatilization rate, indicating that penetration into the leaves had occurred. © 2006 American Chemical Society.

The article presents the calculation of aerodynamic coefficients of an airship wing's design: sustentation and moment coefficient applying two methods of integration. As a theoretical part, the fine theory of the aerodynamic profile is used and as a calculation tool the MATLAB software is used, through programs which are presented in their respective files. Besides, the outcome of results reports are presented., El artículo presenta el cálculo de los coeficientes aerodinámicos de diseño del ala de una aeronave: coeficiente de sustentación y del momento aplicando dos métodos de integración fina del perfil aerodinámico y como herramienta de cálculo se emplea el software MATLAB®, mediante programas que son presentados en los archivos respectivos. Asimismo se presentan los reportes de salida o resultados.

In this paper it is continued an analysis of blade design solutions for small power Vertical Axis Wind Turbines (VAWTs), investigating the best solution for a new design that has as objective the minimisation of vibrations, loads, and augmentation of power. It is investigated a classical Darrieus rotor with a NACA0018 blade profile, and then, it is studied the influence of blade flaps on the performance of the aerodynamic profile, aiming to improve the blade lift curve and the CL/CD ratio. It is concluded that the flaps are proven to be an optimized solution in view of aerodynamic performance of the profile, but only up to a certain angle, and thus, it encourages the further studies regarding their feasibility and their effect on the turbine performance.