Nuclear Waste Disposal Simulations: Couplex Test Cases     

H. Hoteit  Ph. Ackerer  R. Mosé 《Computational Geosciences》2004,8(2):99-124

We give some results obtained for the Couplex test cases proposed by the ANDRA. In this paper our aim is twofold. Firstly, to compute the release of nuclides out of the repository by concentrating on the 3D near field (Couplex 2). The simulation of the transport phenomena takes into account the dissolution of the glass containers and congruent emissions of the radio-nuclides including filiation chains and some simplified chemistry. Secondly, it is to use the near field computations in order to simulate the nuclide migrations in a 2D far field (Couplex 3). Coupling in between the two simulations takes into consideration the periodicity of the disposal modules and the geometry of the repository described in Couplex 1. The mixed finite element and discontinuous Galerkin methods are used to solve the convection–diffusion equations. In order to handle the nonlinear precipitation/dissolution term, we developed a new iterative technique that combines Picard and Newton–Raphson methods.  相似文献   

Asymptotic Analysis and Layer Decomposition for the Couplex Exercise     

Stephane Del Pino  Olivier Pironneau 《Computational Geosciences》2004,8(2):149-162

This document explores the possibilities of multiscale expansions and domain decomposition to solve part of the Couplex 1 exercise. We concentrate on the hydrostatic pressure and show that the slenderness of the domain and the large variations of the Darcy constants allows an analytical approximation which our test reveals to be true to relative errors smaller than 10^–3. The numerical tests are done in 2D with freefem+ and in 3D with freefem3D. Some considerations are also given for Iodine transport.  相似文献   

At the heart of the cultural approach in geography: Thinking space     

Paul Claval 《GeoJournal》2004,60(4):321-328

The way that space is thought of is at the heart of the cultural approach in geography. The passing down of all the components of a culture depends upon the way data is aquired and processed, the results memorized or broadcast. Communication shapes the experience and the knowledge of space and time. It gives to everyone the idea that the real world is doubled by a beyond which plays a central role in social life, since it is upon such a beyond that normative thinking relies and that a significance is given to individual and social life. The spheres of lived-in and known space and time, as well as that of the beyond, vary according to available technologies. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Modélisation du transport réactif en milieux poreux non saturés avec une méthode ELLAM en maillage variable     

Anis Younes 《Comptes Rendus Geoscience》2004,336(6):547-552

Modelling contaminant transfer with biological/chemical/radioactive processes needs appropriate numerical methods able to reproduce sharp concentration fronts. In this work, we develop a new Eulerian–Lagrangian Localized Adjoint Method (ELLAM) for solving the reactive transport equation with non-constant coefficients. To avoid interpolation (leading to errors), we use a moving grid to define the solution and test functions. The method is used to simulate first the infiltration of solute into a column of unsaturated porous medium and second the multispecies transport. The developed ELLAM gives accurate results without non-physical oscillations or numerical diffusion, even when using large time steps. To cite this article: A. Younes, C. R. Geoscience 336 (2004).  相似文献   

管井降水技术在多种含水介质基坑工程中的应用          下载免费PDF全文

曹凤学  原波  杨冬  何世鸣 《探矿工程》2004,31(8):8-11

结合蚌埠城市中心广场会展中心工程，介绍了管井降水技术在多种含水介质的复杂地质环境下的应用。  相似文献   

Traveltime biases in random media and the S-wave discrepancy   总被引：4，自引：0，他引：4  

A. M. Baig  F. A. Dahlen 《Geophysical Journal International》2004,158(3):922-938

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宁夏气象影视数字化节目制作系统的建立          下载免费PDF全文

吴保国 《山西气象》2005,(2):30-32

在信息传播媒体的竞争日益严酷的时代,面对天气预报节目只依靠简单的画面加解说,拉洋片式传统方法这样一种一成不变的局面,策划创意制作出《天气资讯》节目,打破天气预报节目以往的节目形式和播出形式,以极少的投入获得最大的社会效益和经济效益。  相似文献   

The reflection of plane waves in a poroelastic half-space saturated with inviscid fluid   总被引：8，自引：2，他引：8  

Chi-Hsin Lin  Vincent W. Lee  Mihailo D. Trifunac   《Soil Dynamics and Earthquake Engineering》2005,25(3):205-223

This paper discusses surface displacements, surface strain, rocking, and energy partitioning during reflection-of-plane waves in a fluid-saturated poroelastic half-space. The medium is modeled by Biot's theory, and is assumed to be saturated with inviscid fluid. A linear porosity-modulus relation based on experimental data on sandstones is used to determine the material parameters for Biot's model. Numerical results in terms of angle of incident waves and Poisson's ratio are illustrated for various porosities and degrees of solid frame stiffness. The results show that the amount of solid frame stiffness controls the response of a fluid-saturated porous system. A poroelastic medium with essentially dry-frame stiffness behaves like an elastic medium, and the influence of pore fluid increases as dry-frame stiffness is reduced. The effects of a second P-wave become noticeable in poroelastic media with low dry-frame stiffness.  相似文献   

Scattering of plane SV waves by cylindrical canyons in saturated porous medium   总被引：4，自引：0，他引：4  

Li Weihua  Zhao Chenggang 《Soil Dynamics and Earthquake Engineering》2005,25(12):981-995

On the basis of Biot dynamic theory, an analytic solution of two-dimensional scattering and diffraction of plane SV waves by circular cylindrical canyons in a half space of saturated porous media is presented in this paper for the first time. The solution is obtained by employing the Fourier–Bessel series expansion technique. Parametric studies had been carried out, which includes: the angle of incidence, the frequency of the incident SV wave, the porosity of saturated porous medium and the stiffness and Poisson's ratio of the solid-skeleton. All the outcomes are useful for the seismic analysis of the surface topography conditions.  相似文献   

Penny-shaped fractures revisited     

V. Grechka 《Studia Geophysica et Geodaetica》2005,49(3):365-381

All methods of seismic characterization of fractured reservoirs are based on effective media theories that relate geometrical and material properties of fractures and surrounding rock to the effective stiffnesses. In exploration seismology, the first-order theory of Hudson is the most popular. It describes the effective model caused by the presence of a single set of thin, aligned vertical fractures in otherwise isotropic rock. This model is known to be transversely isotropic with a horizontal symmetry axis (HTI). Following the theory, one can invert the effective anisotropy for the crack density and type of fluid infill of fractures, the quantities of great importance for reservoir appraisal and management.Here I compute effective media numerically using the finite element method. I deliberately construct models that contain a single set of vertical, ellipsoidal, non-intersecting and non-interconnected fractures to check validity of the first-order Hudson’s theory and establish the limits of its applicability. Contrary to conventional wisdom that Hudson’s results are accurate up to crack density e ≈ 0.1, I show that they consistently overestimate the magnitudes of all effective anisotropic coefficients ε^(V), δ^(V), and γ^(V). Accuracy of theoretically derived anisotropy depends on the type of fluid infill and typically deteriorates as e grows. While the theory gives | ε^(V)|, |δ^(V)|, |γ^(V)| and close to the upper bound of the corresponding numerically obtained values for randomly distributed liquid-filled fractures, theoretical predictions of ε^(V), δ^(V) are not supported by numerical computations when the cracks are dry. This happens primarily because the first-order Hudson’s theory makes no attempt to account for fracture interaction which contributes to the final result much stronger for gas- than for liquid-filled cracks. I find that Mori-Tanaka’s theory is superior to Hudson’s for all examined crack densities and both types of fluid infill.The paper was presented at the 11th International Workshop on Seismic Anisotropy (11IWSA) held in St. John’s, Canada in 2004.  相似文献