Temporal behavior of a solute cloud in a heterogeneous porous medium 3. Numerical simulations
Temporal behavior of a solute cloud in a heterogeneous porous medium 3. Numerical simulations
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非均质多孔介质中溶质云的时间行为 3. 数值模拟
DOI：
10.1029/2001wr000436
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发表时间：
2002
影响因子：
5.4
通讯作者：
W. Kinzelbach
中科院分区：
文献类型：
--
作者：
M. Dentz;H. Kinzelbach;S. Attinger;W. Kinzelbach
本文对饱和三维非均匀介质中被动溶质的时间行为进行了系统的数值模拟。地下水流量由具有高斯分布对数导水率的达西方程的线性化解推导而来。用随机游动方法研究了被动溶质的输运，系统地研究了有效弥散系数和系综弥散系数的时间行为。数值结果与文献[Dentz等人，2000a，2000b]中给出的二阶微扰理论表达式以及由Corsin猜想得到的非微扰结果进行了比较。低阶微扰理论本质上是基于小非均匀假设的，而Corsin猜想没有考虑由于微扰级数的高阶项而产生的某些贡献。这些模拟第一次提供了关于这些解析近似的有效性和局限性的系统的定量信息。对于增加的非均质性，观察到与理论预测的输运行为有相当大的偏差。
The article presents systematic numerical simulations of the temporal behavior of a passive solute in a saturated three‐dimensional heterogeneous medium. The groundwater flow is derived from the linearized solution of the Darcy equation with Gauss‐distributed log hydraulic conductivity. The transport of a passive solute is studied by a random‐walk method, which allows for a systematic study of the temporal behavior of the effective and ensemble dispersion coefficients. The numerical results are compared to the second‐order perturbation theory expressions given in two companion papers [ Dentz et al., 2000a , 2000b ] and to nonperturbative results which follow from Corrsin's conjecture. The low‐order perturbation theory is intrinsically based on the assumption of small heterogeneity, while Corrsin's conjecture does not take into account certain contributions due to higher‐order terms of the perturbation series. The simulations yield, for the first time, systematic quantitative information on the validity and the limitations of these analytic approximations. For increasing heterogeneities, considerable deviations from the theoretically predicted transport behavior are observed.