Tornadoes pose a significant danger to human life and structures. Research regarding the effects of tornado-induced loads on residential buildings is in incipient stages and there are no specialized construction standards in place to recommend criteria applicable to structures for withstanding tornadic winds. Three residential house models with different geometries were tested in the Wind-induced Damage Simulator (WDS) built at the University of Ottawa. The WDS is capable of simulating pressures induced by multidirectional and tornadic winds. The peak pressure coefficients were calculated on the walls and roofs of the houses and an analysis was performed on the effects of house model orientation, roof pitch angle, and exposure duration. The peak pressure coefficients were then compared to the NBCC 2015 code to clarify if there were any limitations of the current wind design criteria. It was found that the building orientation did not have a significant effect on pressure coefficient trends and magnitudes on the walls and roofs. For the low roof pitch angle models, it was noticed that the suction on the roof was much greater than the higher roof pitch angle models. An interesting observation was made that found that the leading edge of the walls in the direction of the clockwise tornadic flow were always under greater suction than the trailing edge, which causes a torsional effect on the entire model. When comparing the peak pressure coefficient values to the NBCC 2015 recommended values for the secondary cladding members, it was found that the CpCg stipulated in the code were similar to the experimental tornado Cp’s for the walls. However, the Cp’s on the roof were much greater in the experiments when compared to the NBCC 2015. The CpCg of Zones S and Zone R, which are the edges and central regions of the roof, greatly exceed the minimum values in the NBCC 2015. More experiments for residential house models of different geometries should be conducted in order to propose new tornado-induced pressure coefficients to be used in the design of the structure located in tornado-prone areas.Tornadoes pose a significant danger to human life and structures. Research regarding the effects of tornado-induced loads on residential buildings is in incipient stages and there are no specialized construction standards in place to recommend criteria applicable to structures for withstanding tornadic winds. Three residential house models with different geometries were tested in the Wind-induced Damage Simulator (WDS) built at the University of Ottawa. The WDS is capable of simulating pressures induced by multidirectional and tornadic winds. The peak pressure coefficients were calculated on the walls and roofs of the houses and an analysis was performed on the effects of house model orientation, roof pitch angle, and exposure duration. The peak pressure coefficients were then compared to the NBCC 2015 code to clarify if there were any limitations of the current wind design criteria. It was found that the building orientation did not have a significant effect on pressure coefficient trends and magnitudes on the walls and roofs. For the low roof pitch angle models, it was noticed that the suction on the roof was much greater than the higher roof pitch angle models. An interesting observation was made that found that the leading edge of the walls in the direction of the clockwise tornadic flow were always under greater suction than the trailing edge, which causes a torsional effect on the entire model. When comparing the peak pressure coefficient values to the NBCC 2015 recommended values for the secondary cladding members, it was found that the CpCg stipulated in the code were similar to the experimental tornado Cp’s for the walls. However, the Cp’s on the roof were much greater in the experiments when compared to the NBCC 2015. The CpCg of Zones S and Zone R, which are the edges and central regions of the roof, greatly exceed the minimum values in the NBCC 2015. More experiments for residential house models of different geometries should be conducted in order to propose new tornado-induced pressure coefficients to be used in the design of the structure located in tornado-prone areas.

This thesis presents a study of the wind load forces and their influence on the response of structures. The study is based on the capacity of the Proper Orthogonal Decomposition method (POD) to identify and extract organized patterns that are hidden or embedded inside a complex field. Technically this complex field is defined as a multi-variate random process, which in wind engineering is represented by unsteady pressure signals recorded on multiple points of the surface of a structure. The POD method thus transforms the multi-variate random pressure field into a sequence of load shapes that are uncorrelated with each other. The effect of each uncorrelated load shape on the structural response is relatively easy to evaluate and the individual contributions can be added linearly afterwards. Additionally, since each uncorrelated load shape is associated with a percentage of the total energy involved in the loading process, it is possible to neglect those load shapes with low energy content. Furthermore, the load shapes obtained with the POD often reveal physical flow structures, like vortex shedding, oscillations of shear layers, etc. This later property can be used in conjunction with classical results in fluid mechanics to theorize about the physical nature of different flow mechanics and their interactions. The POD method is well suited to be used in conjunction with the classical modal analysis, not only to calculate the structural response for a given pressure field but to observe the details of the wind-structure interaction. A detailed and complete application is presented here but the methodology is very general since it can be applied to any recorded pressure field and for any type of structure.

O presente trabalho busca através do uso de túnel de vento e de análises computacionais via CFD (Computacional Fluid Dynamics) avaliar o comportamento aerodinâmico que determinadas modificações nas arestas vivas de uma edificação retangular propiciam. No que tange a avaliação em túnel de vento, confeccionou-se modelos rígidos com diversas tomadas de pressão distribuídas nas fachadas dos modelos com o propósito de determinar a distribuição das isolinhas médias de pressão e os coeficientes aerodinâmicos. As simulações computacionais foram feitas a partir do uso do método de Taylor-Galerkin de 2 passos em sua forma explícita. Os modelos numéricos foram discretizados segundo o Método dos Elementos Finitos (MEF) utilizando a técnica de integração reduzida e controle de modos espúrios. A turbulência foi tratada utilizando o modelo de turbulência LES (Large Eddy Simulation), um simulador sintético de turbulência e a viscosidade turbulenta segundo a forma dinâmica. Ao final, concluiu-se que as modificações nas arestas vivas de um edifício alto, inicialmente retangular, são capazes de propiciar reduções significativas nas cargas de arrasto e laterais às quais a edificação estaria sujeita sem as modificações propostas. As isolinhas de pressão determinadas mostraram que há uma grande diferença na distribuição de pressões, sendo as modificações nas arestas capazes de diminuir os coeficientes de pressão experimentados pela estrutura. E que o uso integrado de ferramentas experimentais e numéricas pode propiciar um maior conhecimento e confiabilidade nos resultados obtidos na investigação da resposta aerodinâmica de uma estrutura. Além disso, através da comparação entre resultados experimentais e numéricos, viu-se que ambos apresentaram resultados próximos, demonstrando assim, a evolução dos métodos numéricos em avaliações de problemas de interesse da Engenharia do Vento. / The present work aims to evaluate the aerodynamics behavior that certain types of corner modifications in a rectangular building produce by using wind tunnel and computational analysis by CFD. Regarding the wind tunnel tests, rigid models were built using several pressure taps on their facades in order to determine the average pressure isolines distribution and the aerodynamic coefficients of the reduced models. Computational simulations were made using the two-step Taylor-Galerkin method in its explicit form. The numerical models were discretized according to the Finite Element Method (FEM) using the reduced integration technique and hourglassing control. The turbulence was treated using the Large Eddy Simulation (LES) methodology, a synthetic turbulence simulator and the turbulent viscosity according to the dynamic approach. At the end, it was concluded that the corner modifications in a tall building, initially rectangular, are able to produce significant reductions in drag and lift loads to which the building would be subject without the proposed modifications. The determined pressure isolines showed there is a great difference in the pressure distribution, being the corner modifications able to reduce the pressure coefficients experienced by the structure. And that the integrated use of numerical and experimental tools can provide greater knowledge and reliability in the results obtained in the investigation of the aerodynamic response of a structure. In addition, through the comparison between experimental and numerical results, it was observed that both presented close results, thus demonstrating the evolution of numerical methods in evaluations of problems of Wind Engineering interest.

Antarctic Wind Engineering deals with the effects of wind on the built environment. The assessment of wind induced forces, wind resource and wind driven snowdrifts are the main tasks for a wind engineer when participating on the design of an Antarctic building. While conventional Wind Engineering techniques are generally applicable to the Antarctic environment, there are some aspects that require further analysis due to the special characteristics of the Antarctic wind climate and its boundary layer meteorology. The first issue in remote places like Antarctica is the lack of site wind measurements and meteorological information in general. In order to complement this shortage of information various meteorological databases have been surveyed. Global Reanalyses, produced by the European Met Office ECMWF, and RACMO/ANT mesoscale model simulations, produced by the Institute for Marine and Atmospheric Research of Utrecht University (IMAU), have been validated versus independent observations from a network of 115 automatic weather stations. The resolution of these models, of some tens of kilometers, is sufficient to characterize the wind climate in areas of smooth topography like the interior plateaus or the coastal ice shelves. In contrast, in escarpment and coastal areas, where the terrain gets rugged and katabatic winds are further intensified in confluence zones, the models lack resolution and underestimate the wind velocity. The Antarctic atmospheric boundary layer (ABL) is characterized by the presence of strong katabatic winds that are generated by the presence of surface temperature inversions in sloping terrain. This inversion is persistent in Antarctica due to an almost continuous cooling by longwave radiation, especially during the winter night. As a result, the ABL is stably stratified most of the time and, only when the wind speed is high it becomes near neutrally stratified. This thesis also aims at making a critical review of the hypothesis underlying wind engineering models when extreme boundary layer situations are faced. It will be shown that the classical approach of assuming a neutral log-law in the surface layer can hold for studies of wind loading under strong winds but can be of limited use when detailed assessments are pursued. The Antarctic landscape, mostly composed of very long fetches of ice covered terrain, makes it an optimum natural laboratory for the development of homogeneous boundary layers, which are a basic need for the formulation of ABL theories. Flux-profile measurements, made at Halley Research Station in the Brunt Ice Shelf by the British Antarctic Survery (BAS), have been used to analyze boundary layer similarity in view of formulating a one-dimensional ABL model. A 1D model of the neutral and stable boundary layer with a transport model for blowing snow has been implemented and verified versus test cases of the literature. A validation of quasi-stationary homogeneous profiles at different levels of stability confirms that such 1D models can be used to classify wind profiles to be used as boundary conditions for detailed 3D computational wind engineering studies. A summary of the wind engineering activities carried out during the design of the Antarctic Research Station is provided as contextual reference and point of departure of this thesis. An elevated building on top of sloping terrain and connected to an under-snow garage constitutes a challenging environment for building design. Building aerodynamics and snowdrift management were tested in the von Karman Institute L1B wind tunnel for different building geometries and ridge integrations. Not only for safety and cost reduction but also for the integration of renewable energies, important benefits in the design of a building can be achieved if wind engineering is considered since the conceptual phase of the integrated building design process.

O presente trabalho tem como objetivo o desenvolvimento de um sistema voltado à solução de problemas relacionados à Engenharia do Vento Computacional. Para o tratamento das estruturas turbulentas, a Simulação das Grandes Escalas é empregada. Esta metodologia resolve diretamente as estruturas que governam a dinâmica local do escoamento (grandes escalas) e utiliza modelos para resolver as escalas com características mais universais (pequenas escalas). Neste estudo, os efeitos sub-malha são obtidos a partir do modelo clássico de Smagorinsky. Na análise numérica, o método dos elementos finitos é avaliado a partir da utilização de elementos hexaédricos e uma formulação baseada nas equações governantes de escoamentos quase-incompressíveis. Para reduzir o requerimento de memória computacional, esquemas explícitos para solução de sistemas de equações são empregados. O primeiro aspecto a ser abordado para o desenvolvimento do sistema proposto é a redução do tempo de processamento. Partindo do algoritmo desenvolvido por [Petry, 2002], desenvolvese um estudo a cerca de técnicas computacionais de alto desempenho visando acelerar o processamento dos problemas. Assim, apresenta-se um comparativo entre alocações estática e dinâmica de vetores e matrizes, juntamente a implementação do paralelismo de memória compartilhada utilizando diretivas OpenMP. A verificação do aumento da velocidade de processamento é desenvolvida simulando o escoamento em um domínio contendo um corpo imerso aerodinamicamente rombudo. As técnicas utilizadas permitiram a obtenção de um aumento de aproximadamente cinco vezes em relação ao código originalmente avaliado. Uma importante dificuldade na avaliação de escoamentos externos está na solução numérica de problemas advectivo-dominantes. O esquema de Taylor-Galerkin explícito-iterativo, originalmente presente no código e validado para escoamentos internos, mostrou-se inadequado para avaliação do escoamento externo proposto, apresentando perturbações no campo de pressões e não convergindo para a solução correta do problema. Estas instabilidades persistiram em uma versão alternativa desenvolvida, a qual utilizava funções de interpolação de igual ordem para solução da pressão e velocidade. Para uma análise de escoamentos não confinados, é implementado o esquema temporal de dois passos utilizando funções de interpolação para velocidade e pressão de mesma ordem. Esta configuração apresentou resultados físicos de boa qualidade e importante redução no tempo de processamento. Após a identificação da alternativa que permitiu a avaliação dos resultados sem a presença de perturbações, apresenta-se a análise do escoamento sobre um prisma quadrado bidimensional, privilegiando o monitoramento da velocidade, pressão e energia cinética total da turbulência na linha central do domínio e nas proximidades do obstáculo. Esta avaliação é efetuada em malhas com configurações uniformes e irregulares para um número de Reynolds igual a 22000. / Development of a system to solve problems related to Computational Wind Engineering is the main aim of this work. In order to treat turbulent structures, Large Eddy Simulation is employed. This methodology compute directly scales governing local flow dynamics (large eddies) and it use models to solve those with universal character (small eddies). In this study, the sub-grid effects are considered using the standard Smagorinsky model. In the numerical analysis, hexahedral finite elements are used and a formulation based on the governing equations of quasi-compressible flows. To reduce the computational memory request, explicit schemes to solve the equations system are used. In order to reduce CPU time, an algorithm developed by [Petry, 2002] is evaluated and high-performance techniques aiming to accelerate the problem solution are studied. Thus, it is showed a comparison between dynamic and static allocations of vectors and matrices associated to the implementation of shared-memory parallelization using OpenMP directives. The speed up verification is developed simulating the flow around an immersed bluff body. As a consequence of the techniques employed here, an acceleration of approximately five times with respect of the original computational code is obtained. An important difficulty in the external flow evaluation is the numerical solution of convection dominated flows. The Taylor-Galerkin explicit-iterative scheme, (originally used by the program), which was validated for confined flows, did not present good results for external flows simulations and pressure field perturbations were observed. These instabilities were persevered even in an alternative version, where interpolations functions with the same order were used to compute velocity and pressure (in the original version, constant pressure field at element level were employed). To analyze unbounded flows accurately, a two-step explicit scheme using velocity and pressure interpolation functions with the same order was implemented. This configuration presented physical results with good quality and achieve an important reduction in the processing time. After identification of the best alternative without perturbations of the pressure field, the numerical simulation of the flow around a two-dimensional square cylinder was investigated favoring velocity, pressure and total kinetic energy evaluations along the mid line of the domain and in the obstacle vicinity. These evaluations were effectuated with uniform and stretched meshes for a Reynolds number equal to 22000.

O presente trabalho busca através do uso de túnel de vento e de análises computacionais via CFD (Computacional Fluid Dynamics) avaliar o comportamento aerodinâmico que determinadas modificações nas arestas vivas de uma edificação retangular propiciam. No que tange a avaliação em túnel de vento, confeccionou-se modelos rígidos com diversas tomadas de pressão distribuídas nas fachadas dos modelos com o propósito de determinar a distribuição das isolinhas médias de pressão e os coeficientes aerodinâmicos. As simulações computacionais foram feitas a partir do uso do método de Taylor-Galerkin de 2 passos em sua forma explícita. Os modelos numéricos foram discretizados segundo o Método dos Elementos Finitos (MEF) utilizando a técnica de integração reduzida e controle de modos espúrios. A turbulência foi tratada utilizando o modelo de turbulência LES (Large Eddy Simulation), um simulador sintético de turbulência e a viscosidade turbulenta segundo a forma dinâmica. Ao final, concluiu-se que as modificações nas arestas vivas de um edifício alto, inicialmente retangular, são capazes de propiciar reduções significativas nas cargas de arrasto e laterais às quais a edificação estaria sujeita sem as modificações propostas. As isolinhas de pressão determinadas mostraram que há uma grande diferença na distribuição de pressões, sendo as modificações nas arestas capazes de diminuir os coeficientes de pressão experimentados pela estrutura. E que o uso integrado de ferramentas experimentais e numéricas pode propiciar um maior conhecimento e confiabilidade nos resultados obtidos na investigação da resposta aerodinâmica de uma estrutura. Além disso, através da comparação entre resultados experimentais e numéricos, viu-se que ambos apresentaram resultados próximos, demonstrando assim, a evolução dos métodos numéricos em avaliações de problemas de interesse da Engenharia do Vento. / The present work aims to evaluate the aerodynamics behavior that certain types of corner modifications in a rectangular building produce by using wind tunnel and computational analysis by CFD. Regarding the wind tunnel tests, rigid models were built using several pressure taps on their facades in order to determine the average pressure isolines distribution and the aerodynamic coefficients of the reduced models. Computational simulations were made using the two-step Taylor-Galerkin method in its explicit form. The numerical models were discretized according to the Finite Element Method (FEM) using the reduced integration technique and hourglassing control. The turbulence was treated using the Large Eddy Simulation (LES) methodology, a synthetic turbulence simulator and the turbulent viscosity according to the dynamic approach. At the end, it was concluded that the corner modifications in a tall building, initially rectangular, are able to produce significant reductions in drag and lift loads to which the building would be subject without the proposed modifications. The determined pressure isolines showed there is a great difference in the pressure distribution, being the corner modifications able to reduce the pressure coefficients experienced by the structure. And that the integrated use of numerical and experimental tools can provide greater knowledge and reliability in the results obtained in the investigation of the aerodynamic response of a structure. In addition, through the comparison between experimental and numerical results, it was observed that both presented close results, thus demonstrating the evolution of numerical methods in evaluations of problems of Wind Engineering interest.

O presente trabalho tem como objetivo o desenvolvimento de um sistema voltado à solução de problemas relacionados à Engenharia do Vento Computacional. Para o tratamento das estruturas turbulentas, a Simulação das Grandes Escalas é empregada. Esta metodologia resolve diretamente as estruturas que governam a dinâmica local do escoamento (grandes escalas) e utiliza modelos para resolver as escalas com características mais universais (pequenas escalas). Neste estudo, os efeitos sub-malha são obtidos a partir do modelo clássico de Smagorinsky. Na análise numérica, o método dos elementos finitos é avaliado a partir da utilização de elementos hexaédricos e uma formulação baseada nas equações governantes de escoamentos quase-incompressíveis. Para reduzir o requerimento de memória computacional, esquemas explícitos para solução de sistemas de equações são empregados. O primeiro aspecto a ser abordado para o desenvolvimento do sistema proposto é a redução do tempo de processamento. Partindo do algoritmo desenvolvido por [Petry, 2002], desenvolvese um estudo a cerca de técnicas computacionais de alto desempenho visando acelerar o processamento dos problemas. Assim, apresenta-se um comparativo entre alocações estática e dinâmica de vetores e matrizes, juntamente a implementação do paralelismo de memória compartilhada utilizando diretivas OpenMP. A verificação do aumento da velocidade de processamento é desenvolvida simulando o escoamento em um domínio contendo um corpo imerso aerodinamicamente rombudo. As técnicas utilizadas permitiram a obtenção de um aumento de aproximadamente cinco vezes em relação ao código originalmente avaliado. Uma importante dificuldade na avaliação de escoamentos externos está na solução numérica de problemas advectivo-dominantes. O esquema de Taylor-Galerkin explícito-iterativo, originalmente presente no código e validado para escoamentos internos, mostrou-se inadequado para avaliação do escoamento externo proposto, apresentando perturbações no campo de pressões e não convergindo para a solução correta do problema. Estas instabilidades persistiram em uma versão alternativa desenvolvida, a qual utilizava funções de interpolação de igual ordem para solução da pressão e velocidade. Para uma análise de escoamentos não confinados, é implementado o esquema temporal de dois passos utilizando funções de interpolação para velocidade e pressão de mesma ordem. Esta configuração apresentou resultados físicos de boa qualidade e importante redução no tempo de processamento. Após a identificação da alternativa que permitiu a avaliação dos resultados sem a presença de perturbações, apresenta-se a análise do escoamento sobre um prisma quadrado bidimensional, privilegiando o monitoramento da velocidade, pressão e energia cinética total da turbulência na linha central do domínio e nas proximidades do obstáculo. Esta avaliação é efetuada em malhas com configurações uniformes e irregulares para um número de Reynolds igual a 22000. / Development of a system to solve problems related to Computational Wind Engineering is the main aim of this work. In order to treat turbulent structures, Large Eddy Simulation is employed. This methodology compute directly scales governing local flow dynamics (large eddies) and it use models to solve those with universal character (small eddies). In this study, the sub-grid effects are considered using the standard Smagorinsky model. In the numerical analysis, hexahedral finite elements are used and a formulation based on the governing equations of quasi-compressible flows. To reduce the computational memory request, explicit schemes to solve the equations system are used. In order to reduce CPU time, an algorithm developed by [Petry, 2002] is evaluated and high-performance techniques aiming to accelerate the problem solution are studied. Thus, it is showed a comparison between dynamic and static allocations of vectors and matrices associated to the implementation of shared-memory parallelization using OpenMP directives. The speed up verification is developed simulating the flow around an immersed bluff body. As a consequence of the techniques employed here, an acceleration of approximately five times with respect of the original computational code is obtained. An important difficulty in the external flow evaluation is the numerical solution of convection dominated flows. The Taylor-Galerkin explicit-iterative scheme, (originally used by the program), which was validated for confined flows, did not present good results for external flows simulations and pressure field perturbations were observed. These instabilities were persevered even in an alternative version, where interpolations functions with the same order were used to compute velocity and pressure (in the original version, constant pressure field at element level were employed). To analyze unbounded flows accurately, a two-step explicit scheme using velocity and pressure interpolation functions with the same order was implemented. This configuration presented physical results with good quality and achieve an important reduction in the processing time. After identification of the best alternative without perturbations of the pressure field, the numerical simulation of the flow around a two-dimensional square cylinder was investigated favoring velocity, pressure and total kinetic energy evaluations along the mid line of the domain and in the obstacle vicinity. These evaluations were effectuated with uniform and stretched meshes for a Reynolds number equal to 22000.

O presente trabalho busca através do uso de túnel de vento e de análises computacionais via CFD (Computacional Fluid Dynamics) avaliar o comportamento aerodinâmico que determinadas modificações nas arestas vivas de uma edificação retangular propiciam. No que tange a avaliação em túnel de vento, confeccionou-se modelos rígidos com diversas tomadas de pressão distribuídas nas fachadas dos modelos com o propósito de determinar a distribuição das isolinhas médias de pressão e os coeficientes aerodinâmicos. As simulações computacionais foram feitas a partir do uso do método de Taylor-Galerkin de 2 passos em sua forma explícita. Os modelos numéricos foram discretizados segundo o Método dos Elementos Finitos (MEF) utilizando a técnica de integração reduzida e controle de modos espúrios. A turbulência foi tratada utilizando o modelo de turbulência LES (Large Eddy Simulation), um simulador sintético de turbulência e a viscosidade turbulenta segundo a forma dinâmica. Ao final, concluiu-se que as modificações nas arestas vivas de um edifício alto, inicialmente retangular, são capazes de propiciar reduções significativas nas cargas de arrasto e laterais às quais a edificação estaria sujeita sem as modificações propostas. As isolinhas de pressão determinadas mostraram que há uma grande diferença na distribuição de pressões, sendo as modificações nas arestas capazes de diminuir os coeficientes de pressão experimentados pela estrutura. E que o uso integrado de ferramentas experimentais e numéricas pode propiciar um maior conhecimento e confiabilidade nos resultados obtidos na investigação da resposta aerodinâmica de uma estrutura. Além disso, através da comparação entre resultados experimentais e numéricos, viu-se que ambos apresentaram resultados próximos, demonstrando assim, a evolução dos métodos numéricos em avaliações de problemas de interesse da Engenharia do Vento. / The present work aims to evaluate the aerodynamics behavior that certain types of corner modifications in a rectangular building produce by using wind tunnel and computational analysis by CFD. Regarding the wind tunnel tests, rigid models were built using several pressure taps on their facades in order to determine the average pressure isolines distribution and the aerodynamic coefficients of the reduced models. Computational simulations were made using the two-step Taylor-Galerkin method in its explicit form. The numerical models were discretized according to the Finite Element Method (FEM) using the reduced integration technique and hourglassing control. The turbulence was treated using the Large Eddy Simulation (LES) methodology, a synthetic turbulence simulator and the turbulent viscosity according to the dynamic approach. At the end, it was concluded that the corner modifications in a tall building, initially rectangular, are able to produce significant reductions in drag and lift loads to which the building would be subject without the proposed modifications. The determined pressure isolines showed there is a great difference in the pressure distribution, being the corner modifications able to reduce the pressure coefficients experienced by the structure. And that the integrated use of numerical and experimental tools can provide greater knowledge and reliability in the results obtained in the investigation of the aerodynamic response of a structure. In addition, through the comparison between experimental and numerical results, it was observed that both presented close results, thus demonstrating the evolution of numerical methods in evaluations of problems of Wind Engineering interest.

O presente trabalho tem como objetivo o desenvolvimento de um sistema voltado à solução de problemas relacionados à Engenharia do Vento Computacional. Para o tratamento das estruturas turbulentas, a Simulação das Grandes Escalas é empregada. Esta metodologia resolve diretamente as estruturas que governam a dinâmica local do escoamento (grandes escalas) e utiliza modelos para resolver as escalas com características mais universais (pequenas escalas). Neste estudo, os efeitos sub-malha são obtidos a partir do modelo clássico de Smagorinsky. Na análise numérica, o método dos elementos finitos é avaliado a partir da utilização de elementos hexaédricos e uma formulação baseada nas equações governantes de escoamentos quase-incompressíveis. Para reduzir o requerimento de memória computacional, esquemas explícitos para solução de sistemas de equações são empregados. O primeiro aspecto a ser abordado para o desenvolvimento do sistema proposto é a redução do tempo de processamento. Partindo do algoritmo desenvolvido por [Petry, 2002], desenvolvese um estudo a cerca de técnicas computacionais de alto desempenho visando acelerar o processamento dos problemas. Assim, apresenta-se um comparativo entre alocações estática e dinâmica de vetores e matrizes, juntamente a implementação do paralelismo de memória compartilhada utilizando diretivas OpenMP. A verificação do aumento da velocidade de processamento é desenvolvida simulando o escoamento em um domínio contendo um corpo imerso aerodinamicamente rombudo. As técnicas utilizadas permitiram a obtenção de um aumento de aproximadamente cinco vezes em relação ao código originalmente avaliado. Uma importante dificuldade na avaliação de escoamentos externos está na solução numérica de problemas advectivo-dominantes. O esquema de Taylor-Galerkin explícito-iterativo, originalmente presente no código e validado para escoamentos internos, mostrou-se inadequado para avaliação do escoamento externo proposto, apresentando perturbações no campo de pressões e não convergindo para a solução correta do problema. Estas instabilidades persistiram em uma versão alternativa desenvolvida, a qual utilizava funções de interpolação de igual ordem para solução da pressão e velocidade. Para uma análise de escoamentos não confinados, é implementado o esquema temporal de dois passos utilizando funções de interpolação para velocidade e pressão de mesma ordem. Esta configuração apresentou resultados físicos de boa qualidade e importante redução no tempo de processamento. Após a identificação da alternativa que permitiu a avaliação dos resultados sem a presença de perturbações, apresenta-se a análise do escoamento sobre um prisma quadrado bidimensional, privilegiando o monitoramento da velocidade, pressão e energia cinética total da turbulência na linha central do domínio e nas proximidades do obstáculo. Esta avaliação é efetuada em malhas com configurações uniformes e irregulares para um número de Reynolds igual a 22000. / Development of a system to solve problems related to Computational Wind Engineering is the main aim of this work. In order to treat turbulent structures, Large Eddy Simulation is employed. This methodology compute directly scales governing local flow dynamics (large eddies) and it use models to solve those with universal character (small eddies). In this study, the sub-grid effects are considered using the standard Smagorinsky model. In the numerical analysis, hexahedral finite elements are used and a formulation based on the governing equations of quasi-compressible flows. To reduce the computational memory request, explicit schemes to solve the equations system are used. In order to reduce CPU time, an algorithm developed by [Petry, 2002] is evaluated and high-performance techniques aiming to accelerate the problem solution are studied. Thus, it is showed a comparison between dynamic and static allocations of vectors and matrices associated to the implementation of shared-memory parallelization using OpenMP directives. The speed up verification is developed simulating the flow around an immersed bluff body. As a consequence of the techniques employed here, an acceleration of approximately five times with respect of the original computational code is obtained. An important difficulty in the external flow evaluation is the numerical solution of convection dominated flows. The Taylor-Galerkin explicit-iterative scheme, (originally used by the program), which was validated for confined flows, did not present good results for external flows simulations and pressure field perturbations were observed. These instabilities were persevered even in an alternative version, where interpolations functions with the same order were used to compute velocity and pressure (in the original version, constant pressure field at element level were employed). To analyze unbounded flows accurately, a two-step explicit scheme using velocity and pressure interpolation functions with the same order was implemented. This configuration presented physical results with good quality and achieve an important reduction in the processing time. After identification of the best alternative without perturbations of the pressure field, the numerical simulation of the flow around a two-dimensional square cylinder was investigated favoring velocity, pressure and total kinetic energy evaluations along the mid line of the domain and in the obstacle vicinity. These evaluations were effectuated with uniform and stretched meshes for a Reynolds number equal to 22000.

The rapid growth of high-rise high-density urban areas in coastal and near coastal, hurricane-prone cities has been observed globally and in the United States in recent decades. Favored by modern urban growth and planning policies, this trend is expected to accelerate in future. Recent climate change studies suggest a significant increase in the destructiveness of hurricanes in past 30 years by both increases in lifetime and intensity of hurricanes. Current prescriptive wind design approach does not provide transparent methods and criteria to reliably quantify the performance of buildings as well as the functional requirements necessary to accommodate large populations during extreme wind. Since this approach primarily intends to keep the structural system essentially elastic, the more efficient design may be achievable by allowing controlled inelasticity in structural components. All these facts put a great emphasis on using a reliable wind design and assessment approach evidently describing the performance of high-rise building to wind loads beyond the current design wind loads. This dissertation presents the development of a wind performance-based engineering approach and its practical implementation for three, 47-, 40- and 30-story steel moment frame high-rise buildings. In this study, the nonlinear dynamic responses of the buildings to different wind hazard levels were evaluated by developing 3D nonlinear finite element models and utilizing a wind incremental dynamic analysis (IDA) approach. The wind loading for the 47-story building was measured by conducting wind pressure testing on a scaled rigid model at the Wall of Wind (WOW) facility at Florida International University. For two other buildings wind loads were acquired using TPU Aerodynamic Database. Using the IDA results and adopting available wind performance criteria, a wind performance assessment approach was developed representing the estimated performance levels as a function of the basic wind speed. Three types of wind performance were evaluated: structural component performance; cladding performance to wind-induced shear deformation; and serviceability motion comfort performance. This evaluation indicated remarkable lateral capacity associated with allowing controlled structural nonlinearity, in contrast to considerations required to assure acceptable serviceability and non-structural (e.g. cladding) performances.