Factors Controlling Solute Dilution in Heterogeneous Formations

小行星9522651 拟议的研究的目的是量化的土壤水力传导率，局部分散，和其他因素在控制多孔介质中的稀释的时间行为的异质性的相互作用。 虽然已经广泛研究了异质性对溶解化学品羽流扩散的影响，但异质性对污染物稀释的影响仍有待确定，特别是在示踪剂试验和补救项目中相关的“早期”。 稀释度是通过诸如峰浓度和溶质占据的体积之类的测量来量化的。 扩散由浓度分布的空间二阶矩量化。 在评估地下水污染的环境影响时，除了污染的空间范围之外，还必须能够预测峰值浓度。 在这项工作中，我们将进行理论分析，详细的数值实验，并与现场数据进行比较。 污染物稀释措施将与多孔介质的本构参数，主要是水力传导率的变化。 稀释预测将通过分析近似或“闭包”（其导致确定性方程）和变分分析进行。 将对近似值的性能进行数值评估，并通过与现场实验结果进行比较来评价结果。 这项工作的贡献将是一个更好地了解在非均质多孔介质中的污染物浓度水平的时间演变，并指导从业者评估稀释的污染物在地下环境。

9522651 Kitanidis The objective of the proposed research is to quantify the interaction of heterogeneity in soil hydraulic conductivity, local dispersion, and other factors in controlling the temporal behavior of dilution in porous media. Although the effect of heterogeneity on the spreading of plumes of dissolved chemicals has been studied extensively, the effect of heterogeneity on dilution of contaminants remains to be determined, especially at "early" times, which are relevant in tracer tests and remediation projects. Dilution is quantified by measures such as the peak concentration and the volume occupied by solute. Spreading is quantified by the spatial second moment of the concentration distribution. In assessing environmental impacts of groundwater contamination, if is important to be able to anticipate peak concentration in addition to the spatial extent of contamination. In this work, we will conduct theoretical analysis, detailed numerical experiments, and comparisons with field data. Contaminant dilution measures will be related to the porous media constitutive parameters and, primarily, the variability of hydraulic conductivity. Predictions of dilution will be made via analytical approximations or "closures" which lead to deterministic equations and through variational analysis. The performance of the approximations will be numerically assessed and the results will be evaluated by comparison with results from field experiments. The contribution of this work will be a better understanding of the time-evolution of contaminant concentration levels in heterogeneous porous media, and guidance to the practitioner to assess dilution of contaminants in the subsurface environment.