Computational fluid dynamics (CFD) is the analytical process of predicting fluid flow, mass transfer, chemical reactions, and other related phenomena during the design or manufacturing process. Aggressive use of CFD provides drastic reductions in wind tunnel time and lowers the number of experimental rig tests. CFD saves hundreds of millions of dollars for industries, governments, and national laboratories, offering the potential to deliver superior understanding and insight into the critical physical phenomena limiting component performance. Thus, CFD opens new frontiers in many fields, especially vehicle design. One key strength of CFD is its ability to produce simulations useful in inverse design and optimization problems. However, a simulation in a conventional solver is considerably time-consuming to converge. To enable more efficient and scalable CFD simulations, we leverage the universal approximation property of machine learning using deep neural networks (DNNs) to estimate a surrogate solution to the CFD simulation. We present an implementation of this idea in two different models, one representing the eulerian model for compressible viscous flows and another representing the compressible Navier–Stokes equations. Lastly, we discuss the compressible Navier–Stokes network’s performance by implementing an inverse design problem to know if a gradient descent step of the model w.r.t the shape would grant the optimal solution. After training, predictions from these networks are faster than conventional solvers. The network predicts the flow fields hundreds of times faster than current conventional CFD solvers while maintaining good accuracy. Using the network’s predicted solutions to initialize a CFD solver sufficiently speeds up the simulation.

Metamorphic hydrous, CO2-bearing fluids play a critical role in the global carbon cycle. However, how big this influence is on the global carbon cycle and therefore on global climatic processes, is unknown. The actual amount of CO2 which is released into the atmosphere due to metamorphic processes is still debated. For this purpose, fluid-driven reactions in metamorphic rocks must be studied by tracking fluid-rock interactions along pathways of ancient fluids. In the study presented in this thesis, we study fluid-rock interaction in the southeastern part of the Greek island Syros in the Cycladic Archipelago (Aegean). On Syros fluid-rock interaction is recorded by the preservation of blueschist facies assemblages at greenschist facies conditions along a normal shear zone. Blueschist preservation is caused by a combination of metasomatic addition of SiO2 and Na2O and elevated XCO2 which is maintained by high fluxes of a CO2-bearing, hydrous fluid along the shear zone. This research aims to provide a better understanding of the role of mountain building in the carbon cycle. Flux estimates for climate-forcing fluid components (e.g. carbon) require that their concentration in the fluid, fluid volumes and velocities are known. This will be the focus of future work. Further, whole rock chemistry and the availability of specific minerals will be studied to achieve knowledge about which kind of parameters influence and enhance the propagation of fluids through rocks.

This study area provides a unique opportunity to study the intersection of the Elsinore and West Salton detachment faults in southern California, effusing warm springs, and alteration products in the midst of the fault intersection. Structural mapping and compiling previous maps supply an interpretation of the fault zone geometries within the Tierra Blanca Mountains. Geochemical analysis of the crystalline basement and altered protolith help determine the effects of faulting and fluid flow in the study area. In the Tierra Blanca Mountains, the Elsinore strike-slip fault system transitions from the double-stranded Julian segment and Earthquake Valley fault in the northwest, to the single-stranded Coyote Mountain segment in the southeast. A network of cross faults striking northeast connects the fault segments. The Coyote Mountain segment encounters the inactive West Salton detachment fault in the study area. The detachment fault is a barrier to fluid flow and exhibits primarily brittle deformation, while the Coyote Mountain segment is a conduit for fluid flow along the northeastern flank of the Tierra Blanca Mountains. The damage zone of the Coyote Mountain segment reaches widths up to 500 m and contains intense fracturing and subsidiary faults striking parallel to the main trace. The tonalite protolith is bleached, stained, and altered from water-rock interactions. The most intense bleaching is at a county park, where the protolith is altered to clays and zeolites while the mineralogy of the stained regions contains iron oxides and clinochlore in addition to quartz, Ca-rich albite, and biotite preserved from the protolith. The water chemistry at Agua Caliente hot springs shows the fluid is partially equilibrated. Groundwater temperatures likely reached 75-85°C at depths up to 2.14 km before rising to the surface. Frequent seismicity in the study region is related to the spring characteristics including water level, conductivity, and temperatures. Spring temperature and conductivity displayed three behaviors during the summer 2011 logging period, attributed to seasonal changes and most likely local seismicity as well. Conductivity seems to be the property most influenced by earthquake activity in the area. Changes in fluid chemistry between sampling periods may indicate mixture with other fluid sources.

We examined small-displacement faults in the Jurassic Entrada Sandstone adjacent to the Iron Wash Fault, central Utah east of the San Rafael Swell, in order to describe the nature and timing of past fluid movement and deformation in the Entrada Sandstone. Using field studies, microscopy, and X-ray diffraction analysis, we identified mineralized fractures and cementation features in association with deformation bands and fractures at the interface of the Earthy and Slick Rock Members of the Entrada Sandstone. Where the faults cross the Earthy-Slick Rock Member interface, deformation band faults in the Slick Rock Member become opening-mode fractures in the Earthy Member. These fractures are frequently mineralized with calcite, and goethite pseudomorphs after pyrite, providing evidence of at least two phases of fluid flow from the Entrada reservoir into the caprock in connection with deformation bands. We also observe mineralized fractures, poikilotopic cementation, and spherical to elongate concretions on and within deformation band fins in the Slick Rock Member. These features indicate the presence and movement of fluids parallel to and between deformation band fins. At some sites, deformation band faults and fractures cross and offset the interface; at others, they are present in both units, but deformation band faults do not cross the interface and fractures are not directly connected to any bands. Mineralized fractures are only found at breached-interface sites; evidence for fluid flow in the Slick Rock Member is only found in deformation band fins. Interface crossing and fracture formation is not related to proximity to the Iron Wash Fault. We propose that mesoscale faults can act as seal bypass systems and allow fluid leakage from reservoir rock into overlying less permeable rocks. Deformation bands act as both conduits for and barriers to flow, seen most clearly in deformation band fins where iron staining and mineralization is constrained between sets of bands within the fin. In CO2 or wastewater injection scenarios, interface deformation may prevent successful fluid trapping and cause re-emission of injected fluids.

Flow with separation and reattachment has been encountered in many thermo-fluidic devices. Although it causes energy loss due to pressure drops, it is sometimes intentionally used for heat transfer enhancement. To improve the performance of heat exchangers, understanding the details of such complicated flow and thermal structures is very important. Therefore, attention was paid in this study to a representative typical simple model that can generate separating and reattaching flow called backward-facing step (BFS) flow, the fundamental flow and thermal characteristics of a 3-D BFS flow have been investigated experimentally and a flow modification was also made by numerical simulation aimed to promote the heat transfer enhancement. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

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[pt] O trabalho apresenta uma ampla revisão de conceitos básicos associados ao fluxo multifásico (fluxo simultâneo de dois ou mais fluidos) em meios porosos, bem como técnicas de ensaios e equipamentos utilizados na determinação de permeabilidades efetiva e absoluta em solos saturados e não saturados com água. Com base nesta revisão, e visando a medida da permeabilidade de solos não saturados submetidos a fluxo de misturas gasolina-álcool, foi projetados, construído e colocado em operação um sistema de permeâmetros de parede flexível com controle de sucção; foi desenvolvido um software de controle e implementando um sistema automático de monitoramento da instrumentação eletrônica utilizada para medidas de variação de volume, de pressões e de deslocamentos axiais das amostras desolo; foi implementado um sistema de bomba de fluxo para aplicação de vazões constantes nos ensaios de permeabilidade, e forma desenvolvidos sistemas de medição do volume dos líquidos e gases passando pela amostra sob diferentes gradientes de pressão. Todos os desenvolvimentos projetados e implementados são descritos em detalhe. Características de uso dos equipamentos e aspectos de calibração da instrumentação eletrônica e demais acessórios são discutidos, procurando-se definir limites de trabalhabilidade, eventuais deficiências e técnicas alternativas de ensaios envolvendo o uso de misturas álcool gasolina. Visando avaliar o comportamento dos equipamentos e acessórios desenvolvidos, apresenta-se e discute-se resultados de um programa experimental envolvendo a) o uso de amostras de um solo inerte, incompressível dentro dos níveis de tensões efetivas aplicadas, preparadas em laboratório utilizando técnicas especiais de modo a se obter uma estrutura repetitiva, fracamente cimentada, simulando os solos residuais de gnaisse; b) execução de ensaios de vazão constante visando a determinação da permeabilidade absoluta de amostras saturadas utilizando como fluidos permeantes água, ar gasolina e álcool; c) execução de ensaios de vazão constante visando a determinação das permeabilidades efetivas à água e ao ar de amostras não saturadas, submetidas a sucções constantes variando de cerca de 10 a 60 kPa. Os resultados obtidos indicam que o equipamento desenvolvido e as técnicas experimentais implementadas constituem ferramentas versáteis que possibilitam a determinação direta das permeabilidades absolutas e efetivas de forma relativamente simples e confiáveis. / [en] This work presents a wide revision of basic concepts associated to the multiphase flow (simultaneous flow of two or more fluids) in porous media as well as techniques of test and equipment s used in the determination of effective and absolute permeability in saturated and not saturated soils with water.With basis in this revision, and locking for the measure of saturated soils permeability submitted to flow of mixtures gasoline-alcohol, it was projected, built and placed in operation a system of flexible wall permeameters with suction control; a control software was developed and implementing an automatic system of monitoring of the electronic instrumentation used for measures of change volume, pressures and axial displacements of the soil samples; a flow pump system was implemented for application of constant rate in the permeability test, and systems of measurement of the volume of the liquids and gases were developed going by the sample under different pressure gradients.All the projected developments and implemented are described in detail. Characteristics of the used equipment s and calibration aspects of the electronic instrumentation and other accessories are discussed, trying to define workability limits, eventual deficiencies and techniques alternatives of testing involving the use of alcohol gasoline mixtures. Look in for evaluate the performance of equipment s and developed accessories, are presented and it is discussed results of an experimental program involving a) the use of samples of a inert soil, incompressible between levels of applied effective tensions,prepared in labortory using special techniques in way obtaining a repetitive structure, weakly cemented, simulating the residual soils of gnaisse; b) execution of constant rate test looking for the absolute permeability determination of saturated samples using as percolate fluids water, air, gasoline and alcohol; c) execution of constant rate test looking for the determination of the effective permeability to the water and the air of non saturated samples, submitted to constant suctions varying about 10 to 60 kPa.The obtained results indicate that the developed equipment and the implemented experimental techniques constitute versatile tools that make possible the direct determination of the absolute and effective permeabilities in way relatively simple and you trusted. / [es] EL trabajo presenta una amplia revisión de conceptos básicos asociados al flujo multifásico (flujo simultáneo de Dos o más fluidos) en medios porosos, así como técnicas de ensayos y equipamentos utilizados en la determinación de permeabilidades efectiva y absoluta en suelos saturados y no saturados con agua. Con el objetivo de medir la permeabilidad de suelos no saturados sometidos a flujo de mezclas de gasolina y alcohol, fue proyectados, construido y colocado en operación un sistema de permeámetros de pared flexible con control de succión; se desarrolló un software de control y se implementó un sistema automático de monitoramiento de la instrumentación eletrónica utilizada para medidas de variación de volumen, de presiones y de desplazamientos axiales de las muestras de suelo. Se implementó además; un sistema de bomba de flujo para aplicación de desbordamientos constantes en los ensayos de permeabilidad, y se deasarrollaron sistemas de medición del volumen de los líquidos y gases pasando por la muestra bajo diferentes gradientes de presión. Se detallan todos los desarrollos proyectados e implementaciones. Se discute las características de uso de los equipamentos y aspectos de calibración de la instrumentación eletrónica y demás accesorios, con el objetivo de definir límites de trabajabilidad, eventuales deficiencias y técnicas alternativas de ensayos que envuelven el uso de mezclas de alcohol u gasolina. Para evaluar el comportamiento de los equipos y accesorios desarrollados, se presentan y discuten los resultados de un programa experimental que considera a) el uso de muestras de un suelo inerte, incompresible dentro de los níveles de tensiones efectivas que fueron aplicadas, preparadas en laboratorio utilizando técnicas especiales para obtener una extructura repetitiva, debilmente cimentada, simulando suelos residuales de gnaise; b) ejecución de ensayos de desbordamiento constante visando la determinación de la permeabilidad absoluta de muestras saturadas utilizando como fluidos permeantes agua, ar gasolina y álcool; c) ejecución de ensayos de desbordamiento constante con el objetivo de determinar las permeabilidades efectivas a agua y aire de muestras no saturadas, sometidas a succiones constantes variando entre 10 a 60 kPa. Los resultados obtenidos indican que el equipo desarrollado y las técnicas experimentales implementadas constituyen herramientas versátiles que hacen posible la determinación directa de las permeabilidades absolutas y efectivas de forma relativamente simple y confiables.