CAREER: Revisiting Two Basic Processes in Hydrogeology -- Solute Transport in Heterogeneous Formations and Chemical Mixing in Porous Media

9875995哈维拟议的研究将重新考虑水文地质学中的两个基本过程：溶质通过具有非均匀水力传导性的地层的传输，以及多孔介质中的化学混合和反应。 教育计划将包括建立新的课堂工具，结合联合收割机物理模型与数值模拟，并开发项目，结合研究生教育与当地的水文地质问题。当空间可变的水力传导率导致分散，当它导致非平衡传质？ 水文地质学家和土壤科学家已经发现渗透性的空间异质性强烈地影响地下水中溶质的迁移。 研究人员分为两个主要的思想流派。 第一个模型的质量传递（或双孔隙度）过程的非均质性的影响，并参数化的不动区的大小。 第二个模型的基础上的非均质性运输作为一个分散的，通常是Fickian，过程的影响，并涉及到一个有效的（或宏观）分散系数的渗透率场的空间统计。 我们将进行实验和理论研究，以确定每个模型的适用条件。 特别是，我们将研究引起扩散传质的空间结构类型。化学物质如何在多孔介质中混合和反应？ 在多孔介质中开发精确的反应模型取决于考虑分子在反应之前彼此相遇的方式，机械分散和化学混合（或孔尺度混合）可能不是同义词。 例如，机械分散可能部分是由于溶质运动通过某些孔隙，而不是通过相邻的孔隙。 学生通过在课堂上同时使用物理模型和数值模型来了解自然过程和数学模型之间的联系（和差异）。 这种结合使学生深入了解概念/数学模型与物理现实的关系。 将使用一个液晶投影仪将数值运输模拟的视觉输出直接显示在演示箱上，将模拟的和真实的染料羽流叠加起来，从而将两者结合起来。水文地质学与政策相结合。 学生将通过参与一个为当地社区提供环境和水文专业知识的非营利组织来参与当地水文问题。

9875995HarveyThe proposed research will reconsider two basic processes in hydrogeology: Solute transport through formations with heterogeneous hydraulic conductivity, and chemical mixing and reaction in porous media. The educational initiative will consist of building new classroom tools that combine physical models with numerical simulation, and developing projects that integrate graduate education with local hydrogeologic issues.When does spatially variable hydraulic conductivty cause dispersion and when does it cause nonequilibrium mass transfer? Hydrogeologists and soil scientists have found that spatial heterogeneity in permeability strongly influences the transport of solutes in groundwater. Researchers are divided between two principal schools of thought. The first models the effects of heterogeneity as a mass-transfer (or dual-porosity) process, and parameterizes the size of immobile zones. The second models the effects based on heterogeneity on transport as a dispersive, usually Fickian, process and relates an effective (or macro) dispersion coefficient to the spatial statistics of the permeability field. We will conduct experimental and theoretical research to determine the conditions under which each model is appropriate. In particular, we will investigate the type of spatial structures that give rise to diffusive mass transfer.How do chemicals mix and react to porous media? Developing accurate models of reaction in porous media hinges on accounting for the way molecules meet each other before they can react, and mechanical dispersion and chemical mixing (or pore-scale mixing) may not be synonymous. For example, mechanical dispersion may result, in part, from solute movement through some pores, but not through adjacent pores.Combining physical demonstrations and numerical modeling. Students gain understanding of the connection (and differences) between natural processes and mathematical models by using physical models simultaneously with numerical models in the classroom. The combination gives students insight into the relation of conceptual/mathematical models and physical reality. The two will be joined by using an LCD projector to display the visual output of a numerical transport simulation directly onto a demonstration tank, superimposing the simulated and real dye plumes. Integrating hydrogeology and policy. Students will be engaged in local hydrologic issues by involvement in a nonprofit organization that provides environmental and hydrologic expertise for local communities.