The thesis deals with physical and numerical modelling of downsized model of chimney and its demolition. The properties of downsized physical model, which is made of wooden cubes, are being researched and experimentally tested. The physical experiments are then designed using software FyDiK. Numerical Model is simplified to 2D problem, whereas the problem includes dynamic effects. Conformity of designed software model and physical experiment is tested. The aim of this thesis is to achive the best possible conformity of physical and numerical models.

This study sought to demonstrate the potential applications of the solar chimney for the naturally ventilating a building. Computational fluid dynamics (CFD) was used to model various room configurations to assess ventilation strategies. A parametric study of the solar chimney system was executed, and three-dimensional simulations were compared and validated with experiments. A new definition for the hydraulic diameter that incorporated the chimney geometry was developed to predict the flow regime in the solar chimney system. To mitigate the cost and effort to use experiments to analyze building energy, a mathematical approach was considered. A relationship between small- and full-scale models was investigated using non-dimensional analysis. Multiple parameters were involved in the mathematical model to predict the air velocity, where the predictions were in good agreement with experimental data as well as the numerical simulations from the present study. The second part of the study considered building design optimization to improve ventilation using air changes per hour (ACH) as a metric, and air circulation patterns within the building. An upper vent was introduced near the ceiling of the chimney system, which induced better air circulation by removing the warm air in the building. The study pursued to model a realistic scenario for the solar chimney system, where it investigated the effect of the vent sizes, insulation, and a reasonable solar chimney size. It was shown that it is critical to insulate the backside of the absorber and that the ratio of the conditioned area to chimney volume should be at least 10. Lastly, the application of the solar chimney system for basement ventilation was discussed. Appropriate vent locations in the basement were determined, where the best ventilation was achieved when the duct inlet was located near the ceiling and the exhaust vent was located near the floor of the chimney. Sufficient ventilation was also achieved even for scenarios of a congested building when modeling the presence of multiple people. / Ph. D.

Solar chimney power plants use the buoyancy-nature of heated air to harness the Sun's energy without using solar panels. The flow is driven by a pressure difference in the chimney system, so traditional chimneys are extremely tall to increase the pressure differential and the air's velocity. Computational fluid dynamics (CFD) was used to model the airflow through a solar chimney. Different boundary conditions were tested to find the best model that simulated the night-time operation of a solar chimney assumed to be in sub-Saharan Africa. At night, the air is heated by the energy that was stored in the ground during the day dispersing into the cooler air. It is necessary to model a solar chimney with layer of thermal storage as a porous material for FLUENT to correctly calculate the heat transfer between the ground and the air. The solar collector needs to have radiative and convective boundary conditions to accurately simulate the night-time heat transfer on the collector. To correctly calculate the heat transfer in the system, it is necessary to employ the Discrete Ordinates radiation model. Different chimney configurations were studied with the hopes of designing a shorter solar chimney without decreases the amount of airflow through the system. Clusters of four and five shorter chimneys decreased the air's maximum velocity through the system, but increased the total flow rate. Passive advections wells were added to the thermal storage and were analyzed as a way to increase the heat transfer from the ground to the air. / Master of Science

Thesis (PhD (Civil Engineering))--Stellenbosch University, 2008. / Radical, far-beyond-the-norm innovation engages unknown developmental frontiers outside the familiar fields of standardised practice, requiring new and broad perspectives. This implies significant uncertainty during problem solution – the more radical, the greater the uncertainty. No systematic procedures for managing radical innovation exist. Research managers agree that traditional, standardised innovation approaches do not provide sufficient support for managers to cope with the degree of functional uncertainty typical of radical innovations. An efficient approach for delimiting and describing its uncertainties and managing the development process during the radical innovation process is sought. This thesis synthesizes a methodology for radical innovation from Systems Engineering and Management of Technology theory. Its application in a case study illustrates how it facilitates efficient strategic decision-making during radical innovation. Systems Engineering, by its comprehensive perspective, provides a valuable non-intuitive framework from which required radical innovation functionalities and uncertainties are identified, delimited, characterised and developed. Management of Technology concerns the core theory of technology; its perspective on technology provides the radical innovation process with a means of characterising and delimiting status, potential and uncertainty of functional, technological elements in the system. The resulting Radical Innovation Methodology is verified through application to an emerging renewable energy concept, the Solar Chimney Power Plant, which responds to a demand for innovation aimed at sustainable energy generation. The radically tall chimney structure required by the plant, proposed to stand 1,500 meter tall, serves as a fitting case for illustrating the methodology. Addressing and solving of challenges and uncertainties related to the radically tall structure and associated costs are required toward competence of this concept in a global energy market.

Recent observations have highlighted the shortcomings of traditional thinking about faults and fault patterns. The slip model of faulting, developed by Ze'ev Reches, suggests that four sets of faults, arranged in orthorhombic symmetry about the principal strain axes, can accommodate general, three-dimensional strain. Classic conjugate faults are simply a special case of plane strain. Careful analysis of orthorhombic fault patterns and the tenets of the slip model has led to the development of a practical method for decoding the strain significance of fault systems developed in three-dimensional strain fields. The methods are implicit in a model here called the odd-axis model. This new model calls special attention to the odd axis: the one principal strain with sign opposite the other two, assuming a constant volume deformation. Odd-axis medel equations relate fault set geometry to principal strain magnitudes or ratios, the internal friction angle, φ, and the ratio of average fault slip to average spacing between faults of the same set, R. For systems where R < 0.1, the three principal strain ratios are given by tan²α, -sin²α, and -COS²α, where α is the strike of the fault set(s) measured in the plane perpendicular to the odd axis. The model also predicts slip vector orientations as functions of principal strain ratios and orientations. The kinematic implications of the odd-axis model are compatible with those of the slip model. In this first quantitative field test, both fault models are applied to the Chimney Rock array, a system of orthorhombic faults in the northern San Rafael Swell of central Utah. The odd-axis model uses fault plane and slip vector data from Chimney Rock to predict principal strain ratios (ε(y)/ε(x), ε(y)/ε(z), and ε(x)/ε(z)) of .20, -.16, and -.84. These compare extremely well with the observed values, based on fault separation measurements, of .17, -.15, and -.85. The value of ε(y)/ε(z) predicted by the slip model, -.16, matches exactly the value predicted by the odd-axis model and nearly matches the observed value, which is -.15. The success of the field test at Chimney Rock, and the conceptual agreement of both models, suggest that the new theory can accurately relate orthorhombic fault geometries and three-dimensional strain fields. Furthermore, the results underscore how important it is for geologists to recognize the sensitivity of fault geometry and kinematics to three-dimensional strain.

Estruturas como torres e chaminés industriais são bastante vulneráveis ao fenômeno de desprendimento de vórtices, devido à sua esbeltez e forma rombuda. Além disso, devido ao baixo amortecimento estrutural que possuem, essas estruturas também têm maiores chances de atingir grandes amplitudes de deslocamento, o que é causado pelo efeito de captura. Apesar de esse tipo de estrutura ser considerado simples dos pontos de vista estrutural e aerodinâmico, o estudo das vibrações transversais nessas estruturas é bastante complicado, pois envolve a interação entre tópicos complexos da mecânica dos fluidos e estrutural, tornando a determinação confiável da resposta estrutural um dos problemas mais difíceis da Engenharia do Vento. Ao longo das últimas cinco décadas, diversos pesquisadores vêm estudando esse fenômeno, buscando uma abordagem que consiga considerar todos os tópicos que envolvem o mecanismo de vibração por desprendimento de vórtices. Entretanto, apesar dos esforços, os modelos existentes para a verificação da resposta da estrutura são de caráter empírico, sendo os dois mais aceitos pela comunidade científica o modelo de comprimento de correlação de Ruscheweyh e o modelo matemático espectral de Vickery e Clark, o qual foi posteriormente aprimorado por Vickery e Basu. Primeiramente, são estudados em detalhe esses dois modelos e seus métodos derivados, os quais são apresentados em normas e códigos. Após isso, é feita uma proposta de cálculo de dimensionamento do deslocamento do topo de tais estruturas baseada no modelo de Vickery e Basu e adaptada às necessidades da NBR- 6123. E finalmente, são apresentados dados de 42 estruturas, as quais atingiram grandes amplitudes de vibração em seu topo. Essas estruturas foram dimensionadas segundo as diretrizes de cada um dos métodos estudados neste trabalho, o que demonstrou o bom desempenho do Método II do Eurocódigo, do Método do CICIND e da Proposta III-B para a NBR-6123. / Structures like towers and industrial chimneys are quite vulnerable to the vortex shedding phenomenon, due to their slenderness and non-aerodynamic form. Furthermore, due to their low structural damping, these structures are also more likely to reach large displacement amplitudes, which is caused by the lock-in effect. Although these structures are considered as simple from structural and aerodynamic points of view, the study of cross-wind vibrations in these structures is quite complicated, as it involves the interaction of complex topics of fluid and structural mechanics, turning a reliable determination of the structural response into one of the most complicated problems in Wind Engineering. Over the past five decades, several researchers have been studying this phenomenon, seeking an approach that could consider all topics involving the vibrating mechanism by vortex shedding. However, despite the efforts, the existing models for predicting the response of the structure are empirical, with the two most accepted by the scientific community being the Ruscheweyh’s correlation length model and the Vickery & Clark’s spectral mathematical model, which was further enhanced by Vickery & Basu. Firstly, these two models and their derivative methods, which are reported in standards and codes, are studied in detail. After, a calculation proposal for predicting the top displacement of such structures is presented, which is based on the Vickery & Basu model and adapted to the needs of NBR-6123. Finally, data for 42 real structures which have reached large vibration amplitudes at their tops is presented. These structures were designed according to the guidelines for each of the methods studied in this work, which demonstrated the good performance of the Eurocode II Method, of the CICIND Method and of the NBR-6123 III-B Proposal.

Hundreds of pockmarks and mounds, which seismic reflection sections show to be underlain by chimney-like structures, exist in southeast part of the Vøring plateau, Norwegian continental margin. These chimneys may be representative of a class of feature of global importance for the escape of methane from beneath continental margins and for the provision of a habitat for the communities of chemosynthetic biota. Thinning of the time intervals between reflectors in the flanks of chimneys, observed on several high-resolution seismic sections, could be caused by the presence of higher velocity material such as hydrate or authigenic carbonate, which is abundant at the seabed in pockmarks in this area. Evidence for the presence of hydrate was obtained from cores at five locations visited by the Professor Logachev during TTR Cruise 16, Leg 3 in 2006. Two of these pockmarks, each about 300-m wide with active seeps within them, were the sites of high-resolution seismic experiments employing arrays of 4-component OBS (Ocean-Bottom Seismic recorders) with approximately 100-m separation to investigate the 3D variation in their structure and properties. Shot lines at 50-m spacing, run with mini-GI guns fired at 8-m intervals, provided dense seismic coverage of the sub-seabed structure. These were supplemented by MAK deep-tow 5-kHz profiles to provide very high-resolution detail of features within the top 1-40 m sub-seabed. Travel-time tomography has been used to detail the variation in Vp and Vs within and around the chimneys. Locally high-amplitude reflectors of negative polarity in the flanks of chimneys and scattering and attenuation within the interiors of the chimneys may be caused by the presence of free gas within the hydrate stability field. A large zone of free gas beneath the hydrate stability field, apparently feeding several pockmarks, is indicated by attenuation and velocity pull-down of reflectors.

Over the last decade pockmarks have proven to be important seabed features that provide information about fluid flow on continental margins. Their formation and dynamics are still poorly constrained due to the lack of proper three dimensional imaging of their internal structure. Numerous fluid escape features provide evidence for an active fluid-flow system on the Norwegian margin, specifically in the Nyegga region. In June-July 2006 a high-resolution seismic experiment using Ocean Bottom Seismometers (OBS) was carried out to investigate the detailed 3D structure of a pockmark named G11 in the region. An array of 14 OBS was deployed across the pockmark with 1 m location accuracy. Shots fired from surface towed mini GI guns were also recorded on a near surface hydrophone streamer. Several reflectors of high amplitude and reverse polarity are observed on the profiles indicating the presence of gas. Gas hydrates were recovered with gravity cores from less than a meter below the seafloor during the cruise. Indications of gas at shallow depths in the hydrate stability field show that methane is able to escape through the water-saturated sediments in the chimney without being entirely converted into gas hydrate. An initial 2D raytraced forward model of some of the P wave data along a line running NE-SW across the G11 pockmark shows, a gradual increase in velocity between the seafloor and a gas charged zone lying at ~300 m depth below the seabed. The traveltime fit is improved if the pockmark is underlain by velocities higher than in the surrounding layer corresponding to a pipe which ascends from the gas zone, to where it terminates in the pockmark as seen in the reflection profiles. This could be due to the presence of hydrates or carbonates within the sediments.

Home based interventions are advocated in rural areas against a variety of diseases. The combination of different interventions might have synergistic effects in terms of health improvement and cost effectiveness. However, it is crucial to ensure cultural acceptance. The aim of the study was to develop an effective and culturally accepted home-based intervention package to reduce diarrhoea and lower respiratory illnesses in children. In two rural Peruvian communities we evaluated the performance and acceptance of cooking devices, household water treatments (HWT) and home–hygiene interventions, with qualitative and quantitative methods. New ventilated stove designs reduced wood consumption by 16%. The majority of participants selected solar water disinfection as HWT in a blind tasting. In-depth interviews on hygiene improvement further revealed a high demand for kitchen sinks. After one year of installation the improved chimney stoves and kitchen sinks were all in use. The intervention package was successfully adapted to local customs, kitchen-, home–and hygiene management. High user satisfaction was primarily driven by convenience gains due to the technical improvements and only secondarily by perceived health benefits. / Revisión por pares.

Estruturas como torres e chaminés industriais são bastante vulneráveis ao fenômeno de desprendimento de vórtices, devido à sua esbeltez e forma rombuda. Além disso, devido ao baixo amortecimento estrutural que possuem, essas estruturas também têm maiores chances de atingir grandes amplitudes de deslocamento, o que é causado pelo efeito de captura. Apesar de esse tipo de estrutura ser considerado simples dos pontos de vista estrutural e aerodinâmico, o estudo das vibrações transversais nessas estruturas é bastante complicado, pois envolve a interação entre tópicos complexos da mecânica dos fluidos e estrutural, tornando a determinação confiável da resposta estrutural um dos problemas mais difíceis da Engenharia do Vento. Ao longo das últimas cinco décadas, diversos pesquisadores vêm estudando esse fenômeno, buscando uma abordagem que consiga considerar todos os tópicos que envolvem o mecanismo de vibração por desprendimento de vórtices. Entretanto, apesar dos esforços, os modelos existentes para a verificação da resposta da estrutura são de caráter empírico, sendo os dois mais aceitos pela comunidade científica o modelo de comprimento de correlação de Ruscheweyh e o modelo matemático espectral de Vickery e Clark, o qual foi posteriormente aprimorado por Vickery e Basu. Primeiramente, são estudados em detalhe esses dois modelos e seus métodos derivados, os quais são apresentados em normas e códigos. Após isso, é feita uma proposta de cálculo de dimensionamento do deslocamento do topo de tais estruturas baseada no modelo de Vickery e Basu e adaptada às necessidades da NBR- 6123. E finalmente, são apresentados dados de 42 estruturas, as quais atingiram grandes amplitudes de vibração em seu topo. Essas estruturas foram dimensionadas segundo as diretrizes de cada um dos métodos estudados neste trabalho, o que demonstrou o bom desempenho do Método II do Eurocódigo, do Método do CICIND e da Proposta III-B para a NBR-6123. / Structures like towers and industrial chimneys are quite vulnerable to the vortex shedding phenomenon, due to their slenderness and non-aerodynamic form. Furthermore, due to their low structural damping, these structures are also more likely to reach large displacement amplitudes, which is caused by the lock-in effect. Although these structures are considered as simple from structural and aerodynamic points of view, the study of cross-wind vibrations in these structures is quite complicated, as it involves the interaction of complex topics of fluid and structural mechanics, turning a reliable determination of the structural response into one of the most complicated problems in Wind Engineering. Over the past five decades, several researchers have been studying this phenomenon, seeking an approach that could consider all topics involving the vibrating mechanism by vortex shedding. However, despite the efforts, the existing models for predicting the response of the structure are empirical, with the two most accepted by the scientific community being the Ruscheweyh’s correlation length model and the Vickery & Clark’s spectral mathematical model, which was further enhanced by Vickery & Basu. Firstly, these two models and their derivative methods, which are reported in standards and codes, are studied in detail. After, a calculation proposal for predicting the top displacement of such structures is presented, which is based on the Vickery & Basu model and adapted to the needs of NBR-6123. Finally, data for 42 real structures which have reached large vibration amplitudes at their tops is presented. These structures were designed according to the guidelines for each of the methods studied in this work, which demonstrated the good performance of the Eurocode II Method, of the CICIND Method and of the NBR-6123 III-B Proposal.