Mixing and Reactions in Highly Heterogeneous Media - Can Nonlocal Models handle them?

地下水流中活性污染物运移的准确预测面临的最大挑战之一是考虑地质非均匀性的影响。对于许多真实的生活场景，使用在均匀环境中有效的传统方法进行预测根本无法捕获在现场和实验室实验中观察到的许多复杂特征。 对于非活性污染物的情况下，出现了几个有前途的理论方法。 预测地下水流中的化学反应本质上是一个更复杂的问题，目前尚不清楚针对非反应性污染物提出的新方法是否在这一领域具有同样的成功潜力。本项目的目的是解决的适用性的方法设计的保守运输预测非保守运输的问题。 具体而言，缺乏预测能力的原因和数学描述的需要改进是本研究的主要焦点。这些问题将使用理论，数值模拟和实验室实验的协同方式来解决。这项工作的第一部分将集中在研究混合，这是反应的基本驱动力。数值和实验室实验将在构建的非均质多孔介质和理论预测和实验数据之间的比较将突出这些方法（建模和实验室）中的一个或两个的局限性。实验数据将有助于确定与理论模型相关的基本假设何时以及如何失败，最终目的是规避理论中的限制性假设。这项工作的第二部分侧重于研究化学反应，再次通过实验和理论，以确定是否将混合，本身，在一个理论模型是足以改善预测的反应性运输，或是否修改混合和机制有关的化学反应将是必要的补充现有的models.Current预测工具和方法往往提供政策制定者，法律的当局，在对地下水系统中发生化学反应的污染物做出决策时，利益相关者和管理人员的信息不可靠。对于像水这样宝贵的资源来说，这可能引起极大的关切，因为水在世界许多地方已经很紧张。这项工作的一个具体目标是提高目前的理论认识，活性污染物在地下水系统中的传输。 该项目的成功完成为水文和环境工程界提供了新的、大大改进的工具。这些工具将使专家能够更好地评估和设计战略，以清理和补救已受污染的场地。它还将提供更可靠的信息，以便更好地管理和保护现有地下水资源，并有望帮助指导决策者制定未来的地下水政策。 最后，这项研究将涉及圣母大学本科生和研究生的研究经验。

One of the great challenges in making accurate predictions of reactive contaminant transport in subsurface flows is accounting for the impact of geological heterogeneity. For many real life scenarios, prediction using traditional approaches that are valid in homogeneous environments simply cannot capture many of the complex features that have been observed in field and laboratory experiments. For the case of non-reactive contaminants, several promising theoretical methods have emerged. Predicting chemical reactions in subsurface flows is by its nature a more complex problem and it is not clear whether the novel methods put forth for non-reactive contaminants offer the same potential for success in this area. This project aims to address the applicability of methods designed for conservative transport to the problem of predicting non-conservative transport. Specifically, the reasons for lack of predictive capability and the needed improvement in the mathematical description(s) is a primary focus of this research. These concerns will be addressed using theory, numerical simulations and laboratory experiments in a synergistic manner. The first part of this work will focus on studying mixing, which is a fundamental driver of reactions. Numerical and laboratory experiments will be conducted in constructed heterogeneous porous media and comparisons between theoretical predictions and experimental data will highlight limitations in one or both of these approaches (modeling and laboratory). The experimental data will help to identify when and how fundamental assumptions associated with the theoretical models fail with the ultimate aim of circumventing limiting assumptions in the theory. The second part of this work focuses on studying chemical reactions, again via experiments and theory, to determine whether incorporating mixing, by itself, in a theoretical model is sufficient to improve prediction of reactive transport, or whether modifications of mixing and mechanisms related to chemical reactions will be necessary additions to existing models.Current predictive tools and methods often provide policy makers, legal authorities, stakeholders and managers with unreliable information when it comes to making decisions regarding contaminants that undergo chemical reactions in groundwater systems. For a resource as valuable as water, which is already strained in many parts of the world, this can give rise to great concern. One specific goal of this work is to improve the current theoretical understanding of reactive contaminant transport in groundwater systems. The successful completion of this project holds substantial promise to provide the hydrological and environmental engineering communities with new, substantially improved, tools. These tools will allow experts to better assess and design strategies for cleanup and remediation at already contaminated sites. It will also provide more reliable information to allow for better management and protection strategies of existing groundwater resources and hopefully help guide decision makers in the development of future groundwater policies. Finally, this research will involve research experiences for both undergraduate and graduate students at the University of Notre Dame.