CAREER: Connecting the Scales - Local to Global Scales of Mixing in Heterogeneous Porous Media

混合是导致溶质稀释并使化学物质彼此接触的基本过程。它是水文系统中地球化学反应的关键驱动力。由于在多个尺度上普遍存在的不均匀性，通过地球地下的流动本质上是复杂的。在毫米级，流体必须通过复杂的多孔结构。在米到千米的尺度上，含水层地质组成的不均匀性变得很重要。这些不均匀性中的每一种都以扭曲溶质羽流的形状的方式起作用，这对混合的速度和位置有很大的影响。由于混合强烈影响物质如何稀释和反应，因此有必要更好地理解混合，以最终准确预测惰性和反应性溶质的运动。这项工作的总体目标是开发一个改进的理论框架，异质性如何影响混合。这将通过计算模拟通过各种合成和现实的小规模孔隙结构以及较大规模的地质非均质配置的流动和运输来完成。同时，理论描述的混合，从计算实验的观察驱动，将开发。最终，为了验证这些理论发展，该理论将在之前探索混合和混合驱动现象的实验室实验数据上进行测试。尽管我们将地球视为“水星球”，但全球未受污染的地表水和地下水供应是不可或缺的，但脆弱的自然资源。 必须了解污染形式对淡水供应的威胁，以确保可持续供应，并指导有效的补救和未来发展。然而，不考虑异质性（即含水层地质构成的自然变异性）的传统模型是不够的。例如，国家研究理事会的研究表明，法院命令的补救策略在90%的情况下都不能充分补救受污染的场地。这项工作提供的模型和新颖的理论描述，纳入异质性的影响，最终将提供政策制定者，法律的当局，利益相关者和管理人员与改进的工具，以更好地设计和评估补救战略和保护当前的水资源。此外，为了确保使水的利用更可持续的方法取得成功，公众需要更广泛地了解地下水和污染过程。为此，该项目将利用平板电脑技术的新进展，开发面向K-12和公众的水文教育平板电脑“应用程序”。这项工作将与当地小学、初中和高中教师密切合作。在大学一级，将开设关于非均质地下环境中的流动、运输、混合和反应的新课程。这将包括开发公开共享的在线视频资源，以帮助以有形的方式传达复杂的现象。

Mixing is the fundamental process that leads to the dilution of solutes and brings chemical species into contact with one another. It is a key driver of biogeochemical reactions in hydrologic systems. Flows through the Earth's subsurface are by their nature complex due to the ubiquitous occurrence of heterogeneity at multiple scales. At the millimeter scale the fluid must move through complex porous architectures. At meter to kilometer scales heterogeneity in the geologic makeup of an aquifer becomes important. Each of these heterogeneities acts in such a way as to distort the shape of solute plumes, which can have a strong influence on how quickly and where mixing will occur. Since mixing strongly affects how substances dilute and react, a better understanding of mixing is necessary to ultimately accurately predict movement of both inert and reactive solutes. The overarching goal of this work is to develop an improved theoretical framework of how heterogeneity affects mixing. This will be done by computationally simulating flow and transport through a variety of synthetic and realistic small-scale pore structures as well as larger scale geologically heterogeneous configurations. Simultaneously, theoretical descriptions of mixing, driven by observations from the computational experiments, will be developed. Ultimately, to validate these theoretical developments, the theory will be tested on data from previous laboratory experiments that explore mixing and mixing-driven phenomena.Despite our image of Earth as "the water planet," global supplies of uncontaminated surface and groundwater are indispensable, yet fragile, natural resources. Threats to freshwater supplies in the form of contamination must be understood to assure sustainable supplies, as well as to guide effective remediation and future development. However conventional models that do not account for heterogeneity (i.e. the natural variability in the geologic makeup of aquifers) are inadequate. For example, studies by the National Research Council show that court-ordered remediation strategies can fail to adequately remediate polluted sites 90% of the time. The models and novel theoretical description provided by this work, incorporating the influence of heterogeneity, will ultimately provide policy makers, legal authorities, stakeholders and managers with improved tools to better design and assess remediation strategies and protect current water resources. Additionally, to ensure the success of approaches to making water use more sustainable, a broader understanding of groundwater and contamination processes is needed by the general public. To this end, exploiting novel advances in computer tablet technology, this project will develop educational tablet 'apps' for hydrology education aimed at K-12 and the general public. The work will be conducted in close collaboration with local primary, middle and high school teachers. At the university level new courses on flow, transport, mixing and reactions in heterogeneous subsurface environments will be developed. This will include the development of openly shared online video resources to aid in conveying complex phenomena in a tangible manner.