Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14139号 / 工博第2973号 / 新制||工||1441(附属図書館) / 26445 / UT51-2008-N456 / 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, 教授 後藤 仁志, 准教授 牛島 省 / 学位規則第4条第1項該当

The objective of this Thesis is to devise a system for the "rheology-based design" of non-settling (homogeneous) slurry pipelines that is more conducive to application by practicing engineers without impairing its accuracy or utility for research purposes. The cornerstone is the development of a new rheological model and constitutive equation for homogeneous slurry based on the aggregation/deaggregation of the suspended mineral particles. This “yield plastic” model is shown to describe a family of models that includes the Newtonian, Bingham plastic and Casson models as special cases. It also closely approximates the results of many consistency models, including power law, yield power law, Cross and Carreau-Yasuda. The yield plastic model is then used to develop design equations to determine the pressure-gradient of laminar and turbulent pipe flow. A relative energy dissipation criterion is proposed for the laminar-turbulent transition and shown to be consistent with currently used transition models for Newtonian and Bingham fluids. Finally, a new dimensionless group (the “stress number”) is proposed that is directly proportional to the pressure-gradient and independent of the velocity. When the design equations are presented graphically in terms of the stress number and the plastic Reynolds number, the resulting “design curve diagram” is shown to be a dimensionless (pressure-gradient vs. velocity) pipe flow curve. The net result is that the hydraulic design of homogeneous slurry systems only requires the use of a single constitutive equation and three engineering design equations. The results are presented in a conceptually easy form that will foster an intuitive understanding of non-Newtonian pipe flow. This will assist engineers to understand the impact of slurry rheology when designing, operating and troubleshooting slurry pipelines and, in the future, other slurry related processes. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

A novel modeling approach is applied to karst hydrology. Long-standing problems in karst hydrology and solute transport are addressed using Lattice Boltzmann methods (LBMs). These methods contrast with other modeling approaches that have been applied to karst hydrology. The motivation of this dissertation is to develop new computational models for solving ground water hydraulics and transport problems in karst aquifers, which are widespread around the globe. This research tests the viability of the LBM as a robust alternative numerical technique for solving large-scale hydrological problems. The LB models applied in this research are briefly reviewed and there is a discussion of implementation issues. The dissertation focuses on testing the LB models. The LBM is tested for two different types of inlet boundary conditions for solute transport in finite and effectively semi-infinite domains. The LBM solutions are verified against analytical solutions. Zero-diffusion transport and Taylor dispersion in slits are also simulated and compared against analytical solutions. These results demonstrate the LBM’s flexibility as a solute transport solver. The LBM is applied to simulate solute transport and fluid flow in porous media traversed by larger conduits. A LBM-based macroscopic flow solver (Darcy’s law-based) is linked with an anisotropic dispersion solver. Spatial breakthrough curves in one and two dimensions are fitted against the available analytical solutions. This provides a steady flow model with capabilities routinely found in ground water flow and transport models (e.g., the combination of MODFLOW and MT3D). However the new LBM-based model retains the ability to solve inertial flows that are characteristic of karst aquifer conduits. Transient flows in a confined aquifer are solved using two different LBM approaches. The analogy between Fick’s second law (diffusion equation) and the transient ground water flow equation is used to solve the transient head distribution. An altered-velocity flow solver with source/sink term is applied to simulate a drawdown curve. Hydraulic parameters like transmissivity and storage coefficient are linked with LB parameters. These capabilities complete the LBM’s effective treatment of the types of processes that are simulated by standard ground water models. The LB model is verified against field data for drawdown in a confined aquifer.

The use of only one primary sort of energy is the present trend of aircraft design and its force systens. There are designed electromagnetical force systems for control of ther moving parts of aircraft structure. Great demands are laid on energy and dynamic characteristics at some force systems, especially at aircraft control system, and therefore there are developed electro-hydrostatic actuators, suitable for aircraft for aircraft control system, which could graduallly replace commonly used hydraulic servo-controol system. Not only electric signals but also required electric outputs are led into these electro-hydraulic actuators. Using a hydrostatic converter it is changed into mechanical output controlling the aircraft control system. The goal of work is to set requirements for characteristic and conception of electro – hydrostatic actuators for aircraft control systems. Further, on the basis of theoretical analysis , computer modeling and experiment, the design optimisation of electro-ghydrostatic actuator should be done for small business aircraft from the point of view of dimmensions and dynamic characteristics.

Turbulent flows are encountered in nearly every case where fluid motion is involved. Turbulent flow in pipes is of great practical interest, and the problem of flow in the entry region is of special importance since the great majority of applications are in the realm of developing flow.

When entering into the subject of turbulent flow, it is essential to understand that the kind of flow with which we deal belongs to a particular class known as shear flow. These types of flow comprise flow fields in which relative velocities have been induced by shear stresses rather than by the action of pressure forces. In pipe flow, when the fluid enters through the well-rounded bell from a reservoir or from the calm open air, a uniform velocity distribution occurs at the pipe entrance. Immediately down stream from the entrance of the pipe, the flow is structured with a boundary layer near the wall, and is of uniform velocity profile in the central part. Due to the action of wall friction, the boundary layer grows thicker and thicker downstream. As the mass flux is constant throughout the pipe,’ the central stream must accelerate to compensate for this retardation of the flow near the wall. Finally, the boundary layer thickness reaches the value of pipe radius. The free stream, therefore, disappears from the central part of the pipe. Furthermore, Barbin and Jones (1)* pointed out that following the disappearance of the free stream, further changes in the velocity profile and turbulence structure occur before a fully developed condition is reached* The flow in the inlet region of a pipe is, therefore, a transition from a boundary layer type flow at the entrance to a fully developed flow downstream. The change of the free stream velocity in the entry region causes a greater reduction of the static pressure than that in the fully developed region.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This study focuses on the factors that cause project delays in an industrial hydraulic company. More specifically, the article also addresses the development of on-demand engineered products and the impact of the procurement process on delays. As part of the investigation, the authors assessed the historical data of the projects completed in 2017 before determining the critical path for each project in an attempt to identify which project stages may be improved. After further assessing the resulting data, the planning and procurement procedures were deemed as requiring improvement. Next, the article proposes a training plan and new procedures based on the Project Management Body of Knowledge guidelines for Engineer-to-Order projects. In conclusion, the results showed that delays were effectively reduced after implementing these new procedures in both Project Management stages.

A numerical model was developed for the Mobile Bay system to investigate the impacts associated with certain system alterations. The Adaptive Hydraulics (AdH) Code was used to validate the numerical model for hydrodynamics and transport. Due to the physics based nature of the AdH numerical model, the validated model could be altered to represent the plan conditions (removal of the Mobile Bay Causeway). Comparisons of the base and plan model results indicate the impacts of removing the causeway are not widespread and are primarily limited to Chocolatta Bay and the areas adjacent to the causeway. The model results suggest an increased exchange of water between Chocolatta Bay (north of the causeway) and Mobile Bay for the removed causeway configuration. Chocolatta Bay also experiences an increased inflow from the river systems which result in increased suspended sediment concentrations and sediment deposition.

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