Estudio y validación experimental del efecto de aire interno en un perfil aerodinámico hueco

La presente investigación se llevó a cabo en la Universidad Politécnica de Madrid (España) conjuntamente con la Universidad Nacional Experimental del Táchira (Venezuela). El estudio consistió en diseñar una cavidad interna dentro del perfil aerodinámico 2415-3s, el cual fue desarrollado en la Universidad Técnica Checa (Praga, República Checa). Se realizó un estudio computacional, mediante la técnica del CFD, de diferentes modelos de cavidades internas en este perfil, para seleccionar el diseño más adecuado, fabricando un prototipo en 3D; logrando de esta manera validar la simulación computacional con los datos experimentales obtenidos con los ensayos en el túnel de viento AF6109 de la Universidad Nacional Experimental del Táchira. También se aplicaron técnicas de visualización en el túnel de viento, como líneas de corriente de humo y películas de aceite sobre el perfil aerodinámico. Dicho procedimiento permitió corroborar la validación de la simulación computacional. El perfil aerodinámico seleccionado se denominó 2415-3s-TC, cuya característica principal consiste en tres canales independientes entre sí, alojados dentro de la cavidad interna, permitiendo que el flujo de aire forzado a través de la cavidad, cambiara de dirección, para desembocar lo más tangencialmente, así como, lo más perpendicularmente posible al escalón del perfil aerodinámico 2415-3s. Esta configuración de diseñó permitió elevar el coeficiente de sustentación para ángulos de ataque mayores a 8º, así como para ángulos cercanos al ángulo crítico. ABSTRACT This research was conducted at the Polytechnic University of Madrid (Spain) together with the National Experimental University of Táchira (Venezuela). The study was to design an internal cavity within the airfoil 2415-3s, which was developed in the Czech Technical University (Prague, Czech Republic). A computational study was performed using CFD technique, different models of internal cavities in the profile to select the most appropriate design, manufacturing a prototype 3D; thus achieving validate the computer simulation with experimental data obtained from the tests in the wind tunnel AF6109 of the National Experimental University of Táchira. Visualization techniques were also applied in the wind tunnel, as streamlines smoke and oil films on the airfoil. This procedure corroborated validation of computational simulation. The airfoil selected denominated 2415-3s-TC, whose main characteristic consists of three independent channels each other, housed within the inner cavity, allowing the forced air flow through the cavity, change direction, to lead as more tangentially and, as perpendicular as possible to the step 2415-3s aerofoil. This configuration designed allowed increasing the lift coefficient for higher angles of attack to 8º, and for angles near the critical angle.

Avaliação de conflitos de usos múltiplos de água na bacia hidrográfica do Rio Jaguari - SP, através de simulação computacional

No gerenciamento de recursos hídricos, a bacia hidrográfica é considerada a unidade natural de gestão. Suas características físicas definem um espaço onde a água converge para uma saída comum. O desenvolvimento integrado de uma bacia, bem como os possíveis conflitos ocasionados por demandas concorrentes do mesmo recurso, devem ser administrados respeitando esse conceito de unidade. No caso específico da bacia hidrográfica do Rio Jaguari, existe uma crescente preocupação relacionada aos usos múltiplos da água superficial. O rio Jaguari, importante afluente do Paraíba do Sul no estado de São Paulo, tem suas águas represadas para geração de energia elétrica e regularização de vazões. Nos últimos anos, tem-se constatado um crescente rebaixamento dos níveis operacionais da represa do Jaguari. Segundo estudos da sociedade civil organizada local, a tendência é de esgotamento do reservatório em poucos anos. Este trabalho aborda a questão do rebaixamento dos níveis de Jaguari através da aplicação do software DHI Mike Basin 2000. Trata-se de um simulador genérico para sistemas de recursos hídricos, de ampla aplicação. A bacia do Jaguari é representada em um modelo matemático e são simulados quatro cenários distintos de usos de água na bacia. Verifica-se que o problema é real e requer uma intervenção multi-institucional para ser solucionado.

Avaliação da quantidade e qualidade dos recursos hídricos superficiais da bacia hidrográfica do rio Sapucaí-Mirim (SP) através do simulador computacional Mike Basin

Fundamental a vida e ao desenvolvimento de qualquer sociedade, a água é um bem precioso e limitado que está se esgotando e sendo motivo de preocupação mundial. O desperdício, a distribuição desigual, o aumento do consumo e a degradação da qualidade da água são motivos que a tornaram escassa e trouxeram à tona a importância do planejamento e gerenciamento dos recursos hídricos. Frente a esta situação, este trabalho buscou avaliar a disponibilidade hídrica quantitativa e qualitativa da bacia hidrográfica do rio Sapucaí-Mirim, SP. Através da aplicação do simulador hidrológico MIKE BASIN, foi analisado o desempenho do sistema de recursos hídricos, o conflito existente entre os usos múltiplos e a concentração dos parâmetros OD e DBO nas águas do rio que recebe efluentes domésticos, muitos deles sem nenhum tratamento. Apesar da quantidade de água ser suficiente para atender às demandas, o estudo mostra que a geração de energia elétrica está comprometida e a água está se esgotando qualitativamente, evidenciando a necessidade e urgência de se implantar estações de tratamento de esgoto.

Simulação computacional de sistemas de registro de imagens mamográficas

Neste projeto foi desenvolvido um método computacional para verificação da melhor combinação tela intensificadora - filme para exames mamográficos através do estudo de suas características sensitométricas. O software, desenvolvido em ambiente Delphi para windows, apresenta na tela do microcomputador a imagem a ser obtida para cada tipo de combinação tela intensificadora - filme, utilizando imagens de \"Phantoms\" e de mamas reais. Em razão da ampla quantidade de fatores que influenciam a imagem mamográfica final, tais como magnificação, característica dos filmes e telas intensificadoras e condições da processadora, o método proposto pode proporcionar uma ampla avaliação da qualidade dos sistemas de imagem mamográfica de uma forma simples, rápida e automática, através de procedimentos de simulação computacional. A simulação investigou a influência que um determinado sistema de registro exerce sobre a qualidade da imagem, possibilitando conhecer previamente a imagem final a ser obtida com diferentes equipamentos e sistemas de registro. Dentre os sistemas investigados, três filmes (Kodak Min R 2000, Fuji UM MA-HC e Fuji ADM) e duas telas intensificadoras (Kodak Min R 2000 e Fuji AD Mammo Fine), aquele que apresentou melhores resultados, com melhor qualidade de imagens e menor exposição à paciente foi o de tela Min R 2000 com filme Min R 2000 da Kodak.

Reciprocidade periférica como estratégia para aumento de centralidade: estudo de rede de citações acadêmicas

Esta tese apresenta uma configuração em que, numa rede social regida pelo princípio da ligação preferencial, nós periféricos buscam inflacionar artificialmente seus índices de centralidade, medida pelo grau de entrada, por meio do privilégio temporário da reciprocidade de ligações com outros nós periféricos. Para construir este cenário, criou-se uma rede com as características de uma rede acadêmica de citações entre artigos, em que os nós são artigos publicados por um conjunto de periódicos, e as ligações entre eles são as citações que cada artigo faz a outros artigos existentes. Esta rede foi condensada em outra, na qual os nós são os periódicos aos quais cada artigo da primeira rede está associado, e as ligações são o total de citações que os artigos de um periódico faz aos artigos de cada outro periódico. Implementou-se um método de simulação computacional, no qual, durante alguns ciclos, foram manipulados parâmetros relacionados à quantidade total de ligações (citações) entre periódicos periféricos, de forma a induzir os efeitos desejados de reciprocidade periférica, alterando a lógica de direcionamento de citações pela atribuição de maior probabilidade para que artigos de outros periódicos periféricos recebessem ligações, afastando-se da lógica da ligação preferencial, porém sem alterar qualquer outra característica intrínseca que representasse a capacidade de um artigo ou periódico atrair novas ligações. Chamou-se esta alteração da lógica de alocação de ligações entre periódicos periféricos de Comportamento Estratégico. Observou-se que o Comportamento Estratégico é capaz de trazer benefícios de centralidade medida por grau para aqueles periódicos em que ele foi induzido, e prejuízos para os demais periódicos periféricos, porém não é suficiente para que eles saiam do quartil periférico de centralidade a que pertenciam antes da manipulação dos efeitos. Além disso, observou-se que, na ausência de elementos que alterem a capacidade intrínseca de atração de ligações de um periódico, a interrupção do Comportamento Estratégico levou aos níveis anteriores de centralidade. Também se observou que o Comportamento Estratégico acarretou em alterações de centralidade medida por autovetor estatisticamente significativas, porém não esperadas, mas que, após sua interrupção, esta retornou aos patamares anteriores à indução dos efeitos.

A utilização da pesquisa operacional para o gerenciamento dos leitos em um hospital particular: estudo de caso baseado em simulação computacional

The hospital is a place of complex actions, where several activities for serving the population are performed such as: medical appointments, exams, surgeries, emergency care, admission in wards and ICUs. These activities are mixed with anxiety, impatience, despair and distress of patients and their families, issues involving emotional balance both for professionals who provide services for them as for people cared by them. The healthcare crisis in Brazil is getting worse every year and today, constitutes a major problem for private hospitals. The patient that comes to emergencies progressively increase, and in contrast, there is no supply of hospital beds in the same proportion, causing overcrowding, declines in the quality of care delivered to patients, drain of professionals of the health area and difficulty in management the beds. This work presents a study that seeks to create an alternative tool that can contribute to the management of a private hospital beds. It also seeks to identify potential issues or deficiencies and therefore make changes in flow for an increase in service capacity, thus reducing costs without compromising the quality of services provided. The tool used was the Computational Simulation –based in discrete event, which aims to identify the main parameters to be considered for a proper modeling of this system. This study took as reference the admission of a private hospital, based on the current scenario, where your apartments are in saturation level as its occupancy rate. The relocation of project beds aims to meet the growing demand for surgeries and hospital admissions observed by the current administration.

Modelagem molecular voltada para a construção de um nanobiossensor para detecção do herbicida Imazaquin

In this study, our goal was develop and describe a molecular model of the enzyme-inhibiting interaction which can be used for an optimized projection of a Microscope Force Atomic nanobiosensor to detect pesticides molecules, used in agriculture, to evaluate its accordance with limit levels stipulated in valid legislation for its use. The studied herbicide (imazaquin) is a typical member of imidazolinone family and is an inhibitor of the enzymatic activity of Acetohydroxiacid Synthase (AHAS) enzyme that is responsible for the first step of pathway for the synthesis of side-chains in amino acids. The analysis of this enzyme property in the presence of its cofactors was made to obtain structural information and charge distribution of the molecular surface to evaluate its capacity of became immobilized on the Microscopy Atomic Force tip. The computational simulation of the system, using Molecular Dynamics, was possible with the force-field parameters for the cofactor and the herbicides obtained by the online tool SwissParam and it was implemented in force-field CHARMM27, used by software GROMACS; then appropriated simulations were made to validate the new parameters. The molecular orientation of the AHAS was defined based on electrostatic map and the availability of the herbicide in the active site. Steered Molecular Dynamics (SMD) Simulations, followed by quantum mechanics calculations for more representative frames, according to the sequential QM/MM methodology, in a specific direction of extraction of the herbicide from the active site. Therefore, external harmonic forces were applied with similar force constants of AFM cantilever for to simulate herbicide detection experiments by the proposed nanobiosensor. Force value of 1391 pN and binding energy of -14048.52 kJ mol-1 were calculated.

Proposta de método para avaliação do desempenho térmico de residências unifamiliares em clima quente e úmido

Nowadays, evaluation methods to measure thermal performance of buildings have been developed in order to improve thermal comfort in buildings and reduce the use of energy with active cooling and heating systems. However, in developed countries, the criteria used in rating systems to asses the thermal and energy performance of buildings have demonstrated some limitations when applied to naturally ventilated building in tropical climates. The present research has as its main objective to propose a method to evaluate the thermal performance of low-rise residential buildings in warm humid climates, through computational simulation. The method was developed in order to conceive a suitable rating system for the athermal performance assessment of such buildings using as criteria the indoor air temperature and a thermal comfort adaptive model. The research made use of the software VisualDOE 4.1 in two simulations runs of a base case modeled for two basic types of occupancies: living room and bedroom. In the first simulation run, sensitive analyses were made to identify the variables with the higher impact over the cases´ thermal performance. Besides that, the results also allowed the formulation of design recommendations to warm humid climates toward an improvement on the thermal performance of residential building in similar situations. The results of the second simulation run was used to identify the named Thermal Performance Spectrum (TPS) of both occupancies types, which reflect the variations on the thermal performance considering the local climate, building typology, chosen construction material and studied occupancies. This analysis generates an index named IDTR Thermal Performance Resultant Index, which was configured as a thermal performance rating system. It correlates the thermal performance with the number of hours that the indoor air temperature was on each of the six thermal comfort bands pre-defined that received weights to measure the discomfort intensity. The use of this rating system showed to be appropriated when used in one of the simulated cases, presenting advantages in relation to other evaluation methods and becoming a tool for the understanding of building thermal behavior

Análise de métodos para aplicação de ventilação natural em projetos de edificações em Natal-RN

Natural ventilation is an efficient bioclimatic strategy, one that provides thermal comfort, healthful and cooling to the edification. However, the disregard for quality environment, the uncertainties involved in the phenomenon and the popularization of artificial climate systems are held as an excuse for those who neglect the benefits of passive cooling. The unfamiliarity with the concept may be lessened if ventilation is observed in every step of the project, especially in the initial phase in which decisions bear a great impact in the construction process. The tools available in order to quantify the impact of projected decisions consist basically of the renovation rate calculations or computer simulations of fluids, commonly dubbed CFD, which stands for Computational Fluid Dynamics , both somewhat apart from the project s execution and unable to adapt for use in parametric studies. Thus, we chose to verify, through computer simulation, the representativeness of the results with a method of simplified air reconditioning rate calculation, as well as making it more compatible with the questions relevant to the first phases of the project s process. The case object consists of a model resulting from the recommendations of the Código de Obras de Natal/ RN, customized according to the NBR 15220. The study has shown the complexity in aggregating a CFD tool to the process and the need for a method capable of generating data at the compatible rate to the flow of ideas and are discarded during the project s development. At the end of our study, we discuss the necessary concessions for the realization of simulations, the applicability and the limitations of both the tools used and the method adopted, as well as the representativeness of the results obtained

Simulação computacional como ferramenta de auxílio ao projeto: aplicação em edifícios naturalmente ventilados no clima de Natal/RN

Natural air ventilation is the most import passive strategy to provide thermal comfort in hot and humid climates and a significant low energy strategy. However, the natural ventilated building requires more attention with the architectural design than a conventional building with air conditioning systems, and the results are less reliable. Therefore, this thesis focuses on softwares and methods to predict the natural ventilation performance from the point of view of the architect, with limited resource and knowledge of fluid mechanics. A typical prefabricated building was modelled due to its simplified geometry, low cost and occurrence at the local campus. Firstly, the study emphasized the use of computational fluid dynamics (CFD) software, to simulate the air flow outside and inside the building. A series of approaches were developed to make the simulations possible, compromising the results fidelity. Secondly, the results of CFD simulations were used as the input of an energy tool, to simulate the thermal performance under different rates of air renew. Thirdly, the results of temperature were assessed in terms of thermal comfort. Complementary simulations were carried out to detail the analyses. The results show the potentialities of these tools. However the discussions concerning the simplifications of the approaches, the limitations of the tools and the level of knowledge of the average architect are the major contribution of this study

Proposta de método para avaliação do desempenho térmico de residências unifamiliares em clima quente e úmido

Nowadays, evaluation methods to measure thermal performance of buildings have been developed in order to improve thermal comfort in buildings and reduce the use of energy with active cooling and heating systems. However, in developed countries, the criteria used in rating systems to asses the thermal and energy performance of buildings have demonstrated some limitations when applied to naturally ventilated building in tropical climates. The present research has as its main objective to propose a method to evaluate the thermal performance of low-rise residential buildings in warm humid climates, through computational simulation. The method was developed in order to conceive a suitable rating system for the athermal performance assessment of such buildings using as criteria the indoor air temperature and a thermal comfort adaptive model. The research made use of the software VisualDOE 4.1 in two simulations runs of a base case modeled for two basic types of occupancies: living room and bedroom. In the first simulation run, sensitive analyses were made to identify the variables with the higher impact over the cases´ thermal performance. Besides that, the results also allowed the formulation of design recommendations to warm humid climates toward an improvement on the thermal performance of residential building in similar situations. The results of the second simulation run was used to identify the named Thermal Performance Spectrum (TPS) of both occupancies types, which reflect the variations on the thermal performance considering the local climate, building typology, chosen construction material and studied occupancies. This analysis generates an index named IDTR Thermal Performance Resultant Index, which was configured as a thermal performance rating system. It correlates the thermal performance with the number of hours that the indoor air temperature was on each of the six thermal comfort bands pre-defined that received weights to measure the discomfort intensity. The use of this rating system showed to be appropriated when used in one of the simulated cases, presenting advantages in relation to other evaluation methods and becoming a tool for the understanding of building thermal behavior

Análise de métodos para aplicação de ventilação natural em projetos de edificações em Natal-RN

Natural ventilation is an efficient bioclimatic strategy, one that provides thermal comfort, healthful and cooling to the edification. However, the disregard for quality environment, the uncertainties involved in the phenomenon and the popularization of artificial climate systems are held as an excuse for those who neglect the benefits of passive cooling. The unfamiliarity with the concept may be lessened if ventilation is observed in every step of the project, especially in the initial phase in which decisions bear a great impact in the construction process. The tools available in order to quantify the impact of projected decisions consist basically of the renovation rate calculations or computer simulations of fluids, commonly dubbed CFD, which stands for Computational Fluid Dynamics , both somewhat apart from the project s execution and unable to adapt for use in parametric studies. Thus, we chose to verify, through computer simulation, the representativeness of the results with a method of simplified air reconditioning rate calculation, as well as making it more compatible with the questions relevant to the first phases of the project s process. The case object consists of a model resulting from the recommendations of the Código de Obras de Natal/ RN, customized according to the NBR 15220. The study has shown the complexity in aggregating a CFD tool to the process and the need for a method capable of generating data at the compatible rate to the flow of ideas and are discarded during the project s development. At the end of our study, we discuss the necessary concessions for the realization of simulations, the applicability and the limitations of both the tools used and the method adopted, as well as the representativeness of the results obtained

Simulação computacional como ferramenta de auxílio ao projeto: aplicação em edifícios naturalmente ventilados no clima de Natal/RN

Natural air ventilation is the most import passive strategy to provide thermal comfort in hot and humid climates and a significant low energy strategy. However, the natural ventilated building requires more attention with the architectural design than a conventional building with air conditioning systems, and the results are less reliable. Therefore, this thesis focuses on softwares and methods to predict the natural ventilation performance from the point of view of the architect, with limited resource and knowledge of fluid mechanics. A typical prefabricated building was modelled due to its simplified geometry, low cost and occurrence at the local campus. Firstly, the study emphasized the use of computational fluid dynamics (CFD) software, to simulate the air flow outside and inside the building. A series of approaches were developed to make the simulations possible, compromising the results fidelity. Secondly, the results of CFD simulations were used as the input of an energy tool, to simulate the thermal performance under different rates of air renew. Thirdly, the results of temperature were assessed in terms of thermal comfort. Complementary simulations were carried out to detail the analyses. The results show the potentialities of these tools. However the discussions concerning the simplifications of the approaches, the limitations of the tools and the level of knowledge of the average architect are the major contribution of this study

An enhanced method for determining the maximum strain a pipeline coating could tolerate

An enhanced mandrel bend testing method has been proposed for the evaluation of the maximum strain level that could be tolerated by an organic coating, and for the understanding of localised coating deformation and cracking behaviours under nonuniform mechanical strains. The aim is to develop a practical method that is suitable for selecting pipeline coatings in order to ensure that the selected coatings have sufficient flexibility to meet the high strain demand during the construction, hydrostatic testing and operation of high pressure pipelines. Two new mandrel bend testing setups have been designed by employing either centre or end clamps in order to improve the uniformity of strain distributions over coated steel coupons, and by using strain gauges to perform in situ measurements of local strains. A series of tests have been carried out to evaluate the new method for testing the flexibility of selected epoxy based pipeline industry coatings. Preliminary computational simulation has also been carried out for assisting the interpretation of mandrel bending test results.

Computational fluid dynamics simulation and turbomachinery code validation of a high pressure ratio radial-inflow turbine

The present study explores reproducing the closest geometry of a high pressure ratio single stage radial-inflow turbine applied in the Sundstrans Power Systems T-100 Multipurpose Small Power Unit. The commercial software ANSYS-Vista RTD along with a built in module, BladeGen, is used to conduct a meanline design and create 3D geometry of one flow passage. Carefully examining the proposed design against the geometrical and experimental data, ANSYS-TurboGrid is applied to generate computational mesh. CFD simulations are performed with ANSYS-CFX in which three-dimensional Reynolds-Averaged Navier-Stokes equations are solved subject to appropriate boundary conditions. Results are compared with numerical and experimental data published in the literature in order to generate the exact geometry of the existing turbine and validate the numerical results against the experimental ones.