Another look at the conceptual fundamentals of porous media upscaling     

G.?ChristakosEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2003,17(5):276-290

We suggest a critical look at the epistemic foundations of the porous media upscaling problem that focuses on conceptual processes at work and not merely on form manipulations. We explore the way in which critical aspects of scientific methodology make their appearance in the upscaling context, thus generating useful effective parameters in practice. The fons et origo of our approach is a conceptual blending of knowledge states that requires the revision of the traditional method of scientific argument underlying most upscaling techniques. By contrast to previous techniques, the scientific reasoning of the proposed upscaling approach is based on a stochastic model that involves teleologic solutions and stochastic logic integration principles. The syllogistic form of the approach has important advantages over the traditional reasoning scheme of porous media upscaling, such as: it allows the rigorous derivation of the joint probability distributions of hydraulic gradients and conductivities across space; it imposes no restriction on the functional form of the effective parameters or the shape of the probability laws governing the random media (non-Gaussian distributions, multiple-point statistics and non-linear models are automatically incorporated); it relies on sound methodological principles rather than being ad hoc; and it offers the rational means for integrating the multifarious core knowledge bases and uncertain site-specific information sources about the subsurface system. Previous upscaling results are derived as special cases of the proposed upscaling approach under limited conditions of porous media flow, a fact that further demonstrates the generalization power of the approach. Our hope is that looking at the upscaling problem in this novel way will direct further attention to the methodological exploration of the problem at the length and the detail that it deserves.I would like to thank Drs. A. Kolovos and D.T. Hristopulos for their valuable comments. The work was supported by grants from the Army Research Office (Grant no. DAAG55–98–1-0289) and the National Institute of Environmental Health Sciences (P42-ES05948 & P30-ES10126).  相似文献   

基于BISQ模型双相各向同性介质中地震波数值模拟   总被引：11，自引：2，他引：9  

孟庆生  何樵登  朱建伟  王德利 《吉林大学学报(地球科学版)》2003,33(2):217-221

基于BISQ机制,推导了双相各向同性介质中弹性波数值模拟方程,并借助交错网格有限差分方法进行了波场模拟。证实了三种波(快纵波、慢纵波、横波SV)的存在和波场特征;在合成地震记录中,观测列三种波的反射,由于各种波相互之间的转换,转换波在地震记录中显示也很清楚,这使得波场变得更为复杂化。  相似文献   

具有弱透水层的多层介质含水系统中污染质运移数值模拟研究——以大庆市纳污湖泡区为例   总被引：3，自引：1，他引：2       下载免费PDF全文

侯杰  李亚新 《地球科学》2000,25(1):66-70

选取大庆市贴不贴泡区具有普遍意义的饱和-非饱和多层介质含水系统中石油类污染为研究对象.在分析水文地质条件的基础上, 利用实验研究获得含水系统中连接上下含水层的弱透水层的渗透规律, 然后运用数值模拟技术建立起此类含水系统中石油类污染质运移数值模拟模型.应用所建模型对污染质的污染趋势进行了预测, 并提出污染控制措施.   相似文献   

Convective stability analysis of the long-term storage of carbon dioxide in deep saline aquifers     

Xiaofeng Xu  Shiyi Chen  Dongxiao Zhang 《Advances in water resources》2006

Deep saline aquifers are one of the most suitable geologic formations for carbon sequestration. The linear and global stability analysis of the time-dependent density-driven convection in deep saline aquifers is presented for long-term storage of carbon dioxide (CO₂). The convective mixing that can greatly accelerate the CO₂ dissolution into saline aquifers arises because the density of brine increases upon the dissolution of CO₂ and such a density difference may induce instability. The effects of anisotropic permeability on the stability criteria, such as the critical time for the appearance of convective phenomena and the critical wavelength of the most unstable perturbation, are investigated with linear and global stability analysis. The linear stability analysis provides a sufficient condition for instability while the global stability analysis yields a sufficient condition for stability. The results obtained from these two approaches are not exactly the same but show a consistent trend, both indicating that the anisotropic system becomes more unstable when either the vertical or horizontal permeability increases.  相似文献   

非均匀介质中交错网格高阶有限差分数值模拟   总被引：5，自引：0，他引：5  

程冰洁  李小凡  徐天吉 《物探化探计算技术》2006,28(4):294-298

地震波场的数值模拟一直是地球物理学的一个重要的研究领域,而在数值正演模拟方法的研究中,计算精度和计算效率是评价该方法有效性及优越性的二个关键问题。这里从一阶速度—应力弹性波动方程出发,着重介绍如何构造离散化模型的网格,如何求解空间导数,如何选取边界条件等内容,从而更有效地提高数值计算的精度与计算效率。文中构造了不同类型的介质模型,并在交错网格中,利用高阶有限差分模拟非均匀介质的波场传播。模拟结果表明,该方法实现简单,具有很好地稳定性和较高的精度,能够直观、高效地反映出介质中波场的传播规律。  相似文献   

多孔介质中水敏性应用的研究综述     

张晓辉  郑西来  林国庆  吴俊文  周骏 《水文地质工程地质》2006,33(4):81-84

水敏现象在石油、岩土和环境工程等领域广泛存在。有效地控制水敏现象的发生，不仅具有科学意义，还有一定的经济价值。本文在广泛查阅国内外研究成果的基础上，总结了水敏性在石油、岩土和环境工程方面应用的研究进展，并在此基础上提出了水敏性研究的发展方向。  相似文献   

Interrelation among several important links in seismic risk analysis     

黄玮琼  吴宣 《地震学报(英文版)》2006,19(3):284-291

Introduction In the probability analysis method of seismic risk considering time-space inhomogeneity of seismic activity and adopted commonly in China (State Seismological Bureau, 1996) (called in-homogeneous distribution model for short), the division of seismic statistical regions, delimitation of potential seismic sources and estimation of seismicity parameters are the main links that affect significantly the estimation of ground motion parameters of a site. HUANG and WU (2005) studied …  相似文献   

Errors due to the anisotropic-common-ray approximation of the coupling ray theory     

L. Klimeš  P. Bulant 《Studia Geophysica et Geodaetica》2006,50(3):463-477

The common-ray approximation eliminates problems with ray tracing through S-wave singularities and also considerably simplifies the numerical algorithm of the coupling ray theory for S waves, but may introduce errors in travel times due to the perturbation from the common reference ray. These travel-time errors can deteriorate the coupling-ray-theory solution at high frequencies. It is thus of principal importance for numerical applications to estimate the errors due to the common-ray approximation applied. The anisotropic-common-ray approximation of the coupling ray theory is more accurate than the isotropic-common-ray approximation. We derive the equations for estimating the travel-time errors due to the anisotropic-common-ray (and also isotropic-common-ray) approximation of the coupling ray theory. The errors of the common-ray approximations are calculated along the anisotropic common rays in smooth velocity models without interfaces. The derivation is based on the general equations for the second-order perturbations of travel time.  相似文献   

多孔介质中非均匀流动特性的染色示踪试验研究   总被引：3，自引：0，他引：3       下载免费PDF全文

王康  张仁铎  缴锡云 《水科学进展》2007,18(5):662-667

通过土壤染色剂进行的4组试验,对不同介质结构条件下的水流和溶质非均匀运动规律,非均匀流动变异信息分布特征关系以及全局性非均匀流动示踪方法进行了研究。结果表明,即使在相对比较均匀的介质条件下,流动也表现出明显的非均匀特性;对数正态分布能够较好的反映水流的运动分布模式,相比水流运动,溶质的运动和分布规律明显不同,表现出更多的不确定性和变异性。  相似文献   

线性粘弹介质中地震波场数值模拟   总被引：1，自引：0，他引：1       下载免费PDF全文

邵志刚  傅容珊  黄建华  刘财 《地球物理学进展》2007,22(4):1135-1141

本文将以往两种粘弹介质中地震波模拟方法的优点结合起来，以模型理论和积分本构方程为基础，从理论上分析了模型对地震波场的影响；采用交错网格有限差分法对粘弹介质中的地震波进行数值模拟.数值计算结果表明该方法不仅便于计算，同时也便于从力学的角度来分析地震波的传播.数值计算结果与理论分析一致，说明这种方法可以更为有效地模拟粘弹介质中地震波的传播.  相似文献