排序方式： 共有48条查询结果，搜索用时 15 毫秒
41.
Mohamed Younes Ahmed Said Taibi Hanène Souli Jean-Marie Fleureau 《Geotechnical and Geological Engineering》2013,31(4):1335-1348
The use of electro-osmosis in geotechnical engineering has been considered since 1930. Its application has been tested in several sectors like the fight against rising damp in porous materials, the consolidation of soils as well as the remediation of the soils contaminated by oil and heavy metals, etc. The paper presents an experimental study of the electrokinetic phenomena resulting from the application of an electric field to argillaceous sandstones. The electroosmotic tests required the development of a completely new experimental device composed of a confining cell, of a system of measurement and control of the pH of the electrolyte near the electrodes, of a system of control and measurement of the voltage and current at the edges of the sample, and of a system of measurement of inlet (anodic) and outlet (cathodic) flows. Various boundary conditions are considered with and without control of pH. In addition, a micro structural modelling of the electrokinetic phenomena makes it possible to quantify the electro osmotic conductivity with a good agreement with experiments. 相似文献
42.
Fracture network modeling is an essential part of the design, development and performance assessment of Enhanced Geothermal Systems. These systems are created from geothermal resources, usually located several kilometers below the surface of the Earth, by establishing a network of connected fractures through which fluid can flow. The depth of the reservoir makes it impossible to make direct measurements of fractures and data are collected from indirect measurements such as geophysical surveys. An important source of indirect data is the seismic event point cloud generated by the fracture stimulation process. Locations of these points are estimated from recorded micro-seismic signals generated by fracture initiation, propagation and slip. This point cloud can be expressed as a set of three-dimensional coordinates with attributes, for example Se ijk ={(x,y,z);?a|x,y,z∈R,?a∈I}. We describe two methods for reconstructing realistic fracture trace lines and planes given the point cloud of seismic events data: Enhanced Brute-Force Search and RANSAC. The methods have been tested on a synthetic data set and on the Habanero data set of Geodynamics’ geothermal project in the Cooper Basin of South Australia. Our results show that the RANSAC method is an efficient and suitable method for the conditional simulation of fracture networks. 相似文献
43.
Traditional flood‐frequency analysis involves the assumption of homogeneity of the flood distribution. However, floods are often generated by heterogeneous distributions composed of a mixture of two or more populations. Differences between the populations may be the result of a number of factors, including seasonal variations in the flood‐producing mechanisms, changes in weather patterns resulting from low‐frequency climate shifts and/or El Niño/La Nina oscillations, changes in channel routing owing to the dominance of within‐channel or floodplain flow, and basin variability resulting from changes in antecedent soil moisture. Not recognizing these physical processes in conventional flood‐frequency analysis probably is the main reason that many frequency distributions do not provide an acceptable fit to flood data. In this paper, we use long‐term hydroclimatic records from the Gila River basin of south‐east and central Arizona in the USA to explore the extent and significance of mixed populations. First, we discuss the probable causes of heterogeneity in the frequency distribution of annual flood and present evidence of its occurrence. Second, we investigate the implications of using various popular homogeneous distributions for predicting peak flows for basins that exhibit mixed population characteristics. Third, we demonstrate how alternative frequency models that explicitly account for floods generated by a mixture of two or more populations are both hydrologically and statistically more appropriate. We illustrate how the selection of the most plausible distribution for flood‐frequency analysis also should be based on hydrological reasoning as opposed to the sole application of the traditional statistical goodness‐of‐fit tests. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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45.
Younes Noorollahi Saeid Mohammadzadeh Bina Hossein Yousefi 《Natural Resources Research》2016,25(2):227-239
In this research, a simulation was performed for evaluating power production from an abandoned geothermal well as an enhanced geothermal system by injecting a secondary fluid. Abandoned wells, due to lack of fluid or very low transmissivity, are regarded among the low-to moderate-temperature resources that have the potential for heat production without any cost for deep drilling. Accordingly, they are taken as suitable sources of energy. In the present paper, an abandoned geothermal well at Meshkinshahr geothermal field in Sabalan district, northwestern Iran, with 3176 m depth was simulated. The bottom-hole temperature of 148 °C, as well as well casing size, and real thermal gradient for well were applied in the model. A 3D heat transfer simulation model was designed by considering a coaxial pipe as a down-hole heat exchanger between surrounding rocks of the well and injected fluid. Injected fluid to the well with specified pressure and temperature receives heat from rocks surrounding the well, until it reaches the bottom of the well and converts to vapor. The vapor returns to the surface from inner pipe with very low heat loss during its return. The inner pipe is isolated by a thin layer having a low heat conductivity to prevent heat loss from the returned fluid. It was observed that obtained heat in the well depends on temperature profile of the well, injection velocity, and fluid mass flow rate. The model results were optimized by selecting suitable parameters such as inlet injection speed and fluid flow rate to achieve the highest temperature of the fluid returned from the well. A binary power plant was also modeled to determine the extractable power using returned fluid as input using ammonia and isobutene, as working fluids in binary cycle. Finally, electric power of 270 kW was generated from well NWS3 using designed down-hole heat exchanger. 相似文献
46.
Piotr K. Kuraś Younes Alila Markus Weiler Dave Spittlehouse Rita Winkler 《水文研究》2011,25(20):3187-3203
Hydrologic models have increasingly been used in forest hydrology to overcome the limitations of paired watershed experiments, where vegetative recovery and natural variability obscure the inferences and conclusions that can be drawn from such studies. Models are also plagued by uncertainty, however, and parameter equifinality is a common concern. Physically‐based, spatially‐distributed hydrologic models must therefore be tested with high‐quality experimental data describing a multitude of concurrent internal catchment processes under a range of hydrologic regimes. This study takes a novel approach by not only examining the ability of a pre‐calibrated model to realistically simulate watershed outlet flows over a four year period, but a multitude of spatially‐extensive, internal catchment process observations not previously evaluated, including: continuous groundwater dynamics, instantaneous stream and road network flows, and accumulation and melt period spatial snow distributions. Many hydrologic model evaluations are only on the comparison of predicted and observed discharge at a catchment outlet and remain in the ‘infant stage’ in terms of model testing. This study, on the other hand, tests the internal spatial predictions of a distributed model with a range of field observations over a wide range of hydroclimatic conditions. Nash‐Sutcliffe model efficiency was improved over prior evaluations due to continuing efforts in improving the quality of meteorological data collection. Road and stream network flows were generally well simulated for a range of hydrologic conditions, and snowpack spatial distributions were well simulated for one of two years examined. The spatial variability of groundwater dynamics was effectively simulated, except at locations where strong stream–groundwater interactions exist. Model simulations overall were quite successful in realistically simulating the spatiotemporal variability of internal catchment processes in the watershed, but the premature onset of simulated snowmelt for one of the simulation years has prompted further work in model development. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
47.
Stewart Cohen Denise Neilsen Scott Smith Tina Neale Bill Taylor Mark Barton Wendy Merritt Younes Alila Philippa Shepherd Roger Mcneill James Tansey Jeff Carmichael Stacy Langsdale 《Climatic change》2006,75(3):331-358
The research activity described in this report is a comprehensive regional assessment of the impacts of climate change on
water resources and options for adaptation in the Okanagan Basin. The ultimate goal of the project is to develop integrated
climate change and water resource scenarios to stimulate a multistakeholder discussion on the implications of climate change
for water management in the region.
The paper describes two main objectives: (a) providing a set of research products that will be of relevance to regional interests
in the Okanagan, and (b) establishing a methodology for participatory integrated assessment of regional climate change impacts
and adaptation that could be applied to climate-related concerns in Canada and other countries.
This collaborative study has relied on field research, computer-based models, and dialogue exercises to generate an assessment
of future implications, and to learn about regional views on the prospects for adaptation. Along the way, it has benefited
from strong partnerships with governments, researchers, local water practitioners, and user groups. Building on the scenario-based
study components, and a series of interviews and surveys undertaken for the water management and adaptation case study components,
a set of stakeholder dialogue sessions were organized which focused on identifying preferred adaptation options and processes
for their implementation. Rather than seeking consensus on the “best” option or process, regional interests were asked to
consider a range of available options as part of an adaptation portfolio that could address both supply side and demand side
aspects of water resources management in the Okanagan.
The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright. 相似文献
48.
In this work, lowest-order Raviart–Thomas and Brezzi–Douglas–Marini mixed methods are considered for groundwater flow simulations.
Typically, mixed methods lead to a saddle-point problem, which is expensive to solve. Two approaches are numerically compared
here to allow an explicit velocity elimination: (1) the well-known hybrid formulation leading to a symmetric positive definite
system where the only unknowns are the Lagrange multipliers and (2) a more recent approach, inspired from the multipoint flux
approximation method, reducing low-order mixed methods to cell-centered finite difference schemes. Selected groundwater flow
scenarios are used for the comparison between hybrid and multipoint approaches. The simulations are performed in the bidimensional
case with a general triangular discretization because of its practical interest for hydrogeologists. 相似文献