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121.
Generation of three dimensional flow fields for statistically anisotropic heterogeneous porous media
M. A. Cushy A. Bellin Y. Rubin 《Stochastic Environmental Research and Risk Assessment (SERRA)》1995,9(1):89-104
A methodology for generating three dimensional (3D) flow fields for statistically anisotropic heterogeneous porous media is presented and demonstrated. The simulated flow fields are shown to exhibit the input spatial correlation structure and observe mass continuity. Sample flow fields are presented in the form of cross sectional slices of the 3D formation. These cross sections demonstrate visually the characteristics of subsurface flow. The method was found to be faster than traditional techniques in terms of its computational requirements. Given this method, it is possible to generate the large number of realizations of a velocity field necessary to compute high order statistics in transport problems. 相似文献
122.
123.
124.
Seismogram synthesis for piecewise heterogeneous media 总被引:4,自引:0,他引:4
Li-Yun Fu 《Geophysical Journal International》2002,150(3):800-808
125.
Sangdon?Lee Richard?M.?Kamens Myoseon?JangEmail author 《Journal of Atmospheric Chemistry》2005,51(2):223-234
Outdoor smog chamber experiments were performed to investigate gas/particle (G/P) partitioning behavior of aldehyde compounds
in atmospheric acidic aerosols. Diesel soot and wood smoke aerosols were selected as acidic aerosols and octanal, decanal,
undecanal, and cis-pinonaldehyde for aldehydes compounds. Aerosol acidity was measured with the equivalent sulfuric acid amounts in aerosol
mass: 0.2–0.6 wt% in diesel soot and 0.04–0.1 wt% in wood smoke aerosols. Experimentally determined partitioning coefficients
of aldehyde along with other classes of semivolatile organic compounds (SOCs) were compared with the estimation. All experimental
G/P partitioning coefficients of aldehyde compounds were 10–200 times higher than estimated partitioning coefficients. Aldehyde
partitioning coefficients in wood soot were similar or less than diesel soot aerosols. 相似文献
126.
127.
The problem of calculating equivalent grid block permeability tensors for heterogeneous porous media is addressed. The homogenization method used involves solving Darcy's equation subject to linear boundary conditions with flux conservation in subregions of the reservoir and can be readily applied to unstructured grids. The resulting equivalent permeability tensor is stable as defined relative to G-convergence. It is proposed to use both conforming and mixed finite elements to solve the local problems and compute approximations from above and below of the equivalent permeability, respectively. Comparisons with results obtained using periodic, pressure and no-flux boundary conditions and the renormalization method are presented. A series of numerical examples demonstrates the effectiveness of the methodology for two-phase flow in heterogeneous reservoirs. 相似文献
128.
EPR核电厂循环水泵房(HPX)给循环冷却水(CRF)系统供水,为抗震Ⅰ类物项,厂址地基中非均质特性的影响尤为重要。以国内某核电厂实际厂址条件为背景,基于ANSYS分析平台建立了泵房-地基三维有限元整体计算模型,细致模拟捕虏体的力学特性和空间分布形态,并提出基于隐式Newmark的静动力时程分析法,对地基竖向变形及承载能力,基础底面接地率、抗滑和抗倾覆稳定性以及泵房主应力分布等进行了综合评价。计算结果表明,在该厂址实际的分布状态情况下,捕虏体的存在对泵房地基的安全性影响较小,局部压应力超标不影响整体稳定性,所评价指标均能满足规范要求,不需要进行地基处理措施,也验证了所建立静动力联合分析模型的可靠性及良好的工程适用性,结合ANSYS软件丰富的单元模型及非线性分析能力,该模型具有解决复杂核电结构非线性动力问题的潜力。 相似文献
129.
基于对数螺旋破坏模式,考虑黏土的非均质特征,采用极限分析上限法推导了盾构隧道掌子面支护力计算公式,通过优化计算得到了不同条件下的最优上限解。采用该破坏模式与已有的模型试验、工程实例进行对比,验证了在非均质土中采用双对数螺旋极限分析上限法的适用性;同时详细分析了在土体不同参数条件下,隧道掌子面支护力、滑动面范围的变化趋势以及工程影响,结果显示在非均质土中,掌子面支护效率的主导因素是初始黏聚力与掌子面超前核心土,最后通过归一化处理得到了非均质土中极限支护力的设计推荐图,可为工程中初步确定盾构隧道掌子面支护压力提供理论依据。 相似文献
130.
Upscaling methods that need to solve local problems subject to boundary conditions are addressed in this article. We define
a new upscaling method based on optimization problems, which can take into account general boundary conditions applied to
local problems. The determination of upscaled permeability leads to minimizing the difference of dissipated energies (or averaged
velocity) at fine and large scale. Using optimal control techniques, we obtain an effective computing algorithm that allows
us to recover, with classical boundary conditions, the well-known results. The uniqueness issue is tackled for the optimization
problems introduced in our approach. We show that the method is stable with respect to G-convergence, a property that establishes
a link with homogenization theory, and finally, 2D numerical experiments are presented. 相似文献