学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-09-25 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2845号 ; 請求記号: 新制/工/1419 ; 整理番号: 25530 / Multiphase flows are governed by three-dimensional Navier Stokes equations for each involved phase. Therefore, solution of these equations for given boundary and initial conditions, in principle, would determine the flow field in time and space. Generally, boundaries between involved phases are not known a priory, but are part of the, solution; or in the case of flows in a porous medium, these boundaries have too complicated geometry to be resolved mathematically. This resulted into development of simplified models, where the level of simplifications determines the model applicability. However, in order to represent simulated flows accurately, the model should include as much as possible relevant mechanisms and fluid properties. In this study, a numerical model is developed based on finite volume method, in which the volume averaged governing equations are solved. In contrary to the simplified models. a full momentum equations for each involved phase is considered. Such model is utilized in the study to investigate commonly adopted simplifications, and their effects on the model applicability. Namely, for the flows in porous media, the effects of acceleration terms in momentum equations are investigated; first for the saturated groundwater flow, and then; for the air/water flow during air injection into initially saturated soil. It is revealed that in the case of saturated flow in homogeneous, incompressible, low permeable soils, the pressure adapts the new imposed boundary conditions instantaneously, while the velocities reach the quasi-steady conditions extremely fast. In the case of heterogeneous soil, pressure and velocity field have transient nature, but quickly reach the quasi-steady conditions. Only during this onset of flow, the inertia terms play a role. In the case of air/water flow during air sparging, it is revealed that acceleration becomes important for porous medium with average grain size larger than 2 rum. This implies that simulations of such flow in coarse sands and gravels should include acceleration. It is explicitly shown that phenomena of flow pulsation, manifesting as steady pulsation at the constant air-injection flow rate, can be modeled only by inclusion of acceleration terms in governing equations. Theoretical analysis; conducted by application of one-dimensional stability analysis, revealed that inertial effects promote the instability, while the capillary forces oppose it. Ratio of these forces determines the onset of instability. It is showed that for materials with average grain size smaller than 2 mm, instability can not be expected. In order to apply the model for simulation of contaminant removal during air sparging, the contaminant transport model is supplied. Mechanistic numerical models inherently assume that involved phases are completely mixed, and by now reported models commonly assume the local equilibrium of contaminant between the air and water phase. As reported by many investigators, this leads toward an overestimated contaminant removal. Therefore, in this model a channel air flow pattern is considered, where transfer of contaminant between the water and the air phase is modeled according to two film theory. Diffusive process of contaminant transport toward the air phase is modeled by a first order kinetic process between two water compartments: a immobile compartment in contact with the air phase and mobile compartment which has no contact with the air phase. Application of the developed model to reported two-dimensional experiment, showed a good agreement between simulated and measured transient change of dissolved contaminant in the water. This study also showed that single numerical model, through the minor refinements, can be applied to wide variety of hydraulic engineering problems. By inclusion of gas compressibility, and mass exchange between the gas and the water phase in continuity equations, with adapting the drag term in momentum equations, a bubble phone model is proposed which can be utilized for simulation of lake amelioration by gas (air or pure oxygen) injection. Model is qualitatively and quantitatively validated by comparison with reported experiments from the literature. Hypothetical simulation of pure oxygen injection into 50 in deep lake showed that, due to ambient water entrainment into the gas plume, a significant spreading of dissolved oxygen can not be expected. Therefore, a optional gas injection strategy should be considered. Developed model can be utilized in order to propose an optimal gas injection design. Finally.. the same numerical model is proposed for simulation of flow in complex flow domains, consisting of bulk water and flow in porous medium with free surface boundary. Model is formulated in generalized curvilinear coordinates, in order to provide adequate representation of irregular boundaries. In contrast to earlier proposed boundary conditions at the two domain interface, in this model a continuity of velocities and stresses is assumed; for both regions a single set of governing equations is solved. Model application is illustrated by simulation of embankment overflow and its effect on effective stresses in the porous medium. It is showed that coupled, bulk water and groundwater flow, significantly influence the slope failure potential, here quantified by the Coulomb failure coefficient for non cohesive soils. / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13374号 / 工博第2845号 / 新制||工||1419(附属図書館) / 25530 / UT51-2007-Q775 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 細田 尚, 准教授 牛島 省, 准教授 後藤 仁志 / 学位規則第4条第1項該当

Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-07T19:57:19Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) victor_luiz_batista_aguiar.pdf: 2508647 bytes, checksum: 87d9596e1cf8e04b90b12aa373fa4748 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-05-08T12:30:45Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) victor_luiz_batista_aguiar.pdf: 2508647 bytes, checksum: 87d9596e1cf8e04b90b12aa373fa4748 (MD5) / Made available in DSpace on 2018-05-08T12:30:45Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) victor_luiz_batista_aguiar.pdf: 2508647 bytes, checksum: 87d9596e1cf8e04b90b12aa373fa4748 (MD5) Previous issue date: 2017 / A crescente demanda pela utiliza??o de recursos h?dricos em nossa sociedade faz com que seja necess?ria a amplia??o dos meios de capta??o de ?gua. As ?guas subterr?neas surgem como alternativa ? capta??o convencional, tendo em vista que o armazenamento da ?gua nas camadas inferiores do solo garanta a manuten??o da qualidade deste recurso, uma vez que passam por processos naturais de filtra??o. Nesse sentido, a caracteriza??o dos sistemas aqu?feros por meio de modelagem matem?tica surge como ferramenta de aux?lio na compreens?o do fluxo subterr?neo local. A presente pesquisa tem como principal objetivo analisar o comportamento hidrogeol?gico do munic?pio de Te?filo Otoni - MG, com base em simula??es oriundas de modelos conceituais, pelo m?todo das diferen?as finitas. Por meio de simula??o de propriedades influentes no transporte h?drico como taxa de recarga, vaz?o de bombeamento de po?os e condutividade hidr?ulica, foi poss?vel observar as varia??es nos valores m?ximos e m?nimos de carga hidr?ulica em pontos discretizados nos limites do modelo conceitual proposto, auxiliando assim no entendimento dos resultados obtidos. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Tecnologia, Sa?de e Sociedade, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The growing demand for the use of water resources in our society makes it necessary to expand the means of abstraction of water. Groundwater emerges as an alternative to conventional abstraction, owing to the storage of water in the lower layers of the soil ensures the maintenance of the quality of this resource, since they undergo natural filtration processes. In this sense, the characterization of the aquifer systems through mathematical modeling appears as a tool to aid in the understanding of the local underground flow. The present research has as main objective to analyze the hydrogeological behavior of Te?filo Otoni - MG, based on simulations derived from conceptual models, by the finite difference method. By means of simulation of influent properties in the water transport as recharge rate, well pumping rate and hydraulic conductivity it was possible to observe the variations in the maximum and minimum values of hydraulic head in discretized points within the limits of the proposed conceptual model, thus helping in the understanding of the results obtained.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The numerical modeling of underground flow of Morro Agudos mine, property of Votorantim Metais Zinco (VMZ), Paracatu-MG, used data from hydrometeorological monitoring campaigns to calibrate the actual scenario and simulate future pumping scenarios of this mine, using Visual MODFLOW 3.1 software. The study area is located in Paracatu-MG and in external portion of BrasÃlia Fold Belt at west margin of SÃo Francisco Craton, the mine is inside metasedimentary sequence of Vazante Group, composed by dolarenite, dolarenitics and dolomitics breccias of Morro do CalcÃrio Formation. In June of 2011 was registered 255mÂ/h of water springs inside underground mine, this value is nearly the maximum capacity, 270mÂ/h, of Wastewater Treatment Plant. So, it was necessary make some simulations to predict the increase of this pumping rate until the year of 2017, following expansion plans, purposing take effective actions in the water treatment. Was used monitoring data given by technical team of VMZ to update the concept hydrogeological model and make a new calibration of numerical model. After calibration, those scenarios were simulated from 2012 until 2017. From those scenarios were obtained an increased pumping rate that will achieve to 530mÂ/h. Of this value was subtracted the pumping rate of "Projeto Ãgua Limpa" (Clean Water Project) and added the inside flow, reaching the final pumping value of 504mÂ/h. This pumping rate will be considered in the planning of the new Wastewater Treatment Plant to supply necessities until 2017. This value can be decreased with rising of "Projeto Ãgua Limpa", but depends of mutual efforts from Hydrogeology, Geology, Environmental and Operations sectors. MineÂs dewatering itÂs not interfering in stream flows around the mine, because all water is pumped to surface and returns to original stream, without being prejudicial or causing environmental impacts. As is a fissural aquifer itÂs impossible to affirm if galleries will cross an expressive fractural zone, increasing in a large way the pumping rate simulated by this work. / O modelamento numÃrico do fluxo subterrÃneo da Mina de Morro Agudo, de propriedade da Votorantim Metais Zinco (VMZ), Paracatu-MG, utilizou os dados do monitoramento hidrometeorolÃgico para calibrar o cenÃrio atual e realizar simulaÃÃes de cenÃrios futuros do bombeamento realizado na mina, utilizando o software Visual MODFLOW 3.1. A Ãrea de estudo localiza-se em Paracatu-MG e encontra-se na parte externa da Faixa de Dobramentos BrasÃlia na margem oeste do CrÃton do SÃo Francisco, a mina està inserida na sequÃncia metassedimentar do Grupo Vazante, composta por dolarenitos, brechas dolarenÃticas e dolomÃticas pertencentes à FormaÃÃo Morro do CalcÃrio. Em Junho de 2011 foi registrado 255mÂ/h em surgÃncias de Ãgua na mina subterrÃnea, valor prÃximo à capacidade mÃxima, 270mÂ/h, da EstaÃÃo de Tratamento de Efluentes. Assim, se fez necessÃrio realizar simulaÃÃes do acrÃscimo desta vazÃo atà o ano 2017, seguindo o plano de expansÃo da mina, com objetivo de subsidiar aÃÃes efetivas no tratamento de Ãgua da unidade. Foram utilizados os dados de monitoramento disponibilizados pela equipe tÃcnica da VMZ para atualizar o modelo hidrogeolÃgico conceitual e realizar nova calibraÃÃo do modelo numÃrico. ApÃs a calibraÃÃo foram realizadas simulaÃÃes a partir do ano 2012 atà 2017. A partir dos cenÃrios simulados foi obtido um acrÃscimo constante nas vazÃes atingindo patamares de 530mÂ/h. Deste valor foi subtraÃda a vazÃo bombeada pelo Projeto Ãgua Limpa e somada a vazÃo aduzida para a mina, chegando ao valor final de bombeamento de 504mÂ/h. Esta à a vazÃo que serà considerada no planejamento da construÃÃo da nova EstaÃÃo de Tratamento de Efluentes para atender as necessidades atà o ano 2017. Essa vazÃo pode ser reduzida com a ampliaÃÃo do Projeto Ãgua Limpa, dependendo de um esforÃo conjunto entre os setores de Hidrogeologia, Meio Ambiente, Geologia e Lavra. O desaguamento da mina nÃo està interferindo na vazÃo dos vertedouros situados no CÃrrego Morro Agudo de maneira definitiva, pois a Ãgua que infiltra na mina subterrÃnea à bombeada para a superfÃcie, tratada e devolvida ao RibeirÃo TraÃras, sem provocar prejuÃzo ou impactos ambientais. Por se tratar de um aquÃfero fissural, nÃo se pode precisar se a lavra irà atingir uma zona aquÃfera fraturada de maior expressÃo, aumentando consideravelmente as vazÃes simuladas.