Solute Transport with Convective Instability in Groundwater

这是一项为期三年的实验、理论和实地研究对流不稳定性及其在质量运输过程中溶质混合中的作用。当密度较大的地下水上覆密度较小的地下水时，在各种地质和水文地质条件下，不稳定性会在不同的尺度上发展。该过程将两种水混合以减少密度分层。该研究的具体目标是在概念上和数学上描述不稳定发展的动力学，并评估不稳定发展对大流量系统中地下水化学演化的影响。这项研究包括实验和对一个实际地下水系统的评价，即米尔克河自流含水层，其中不稳定的混合对水的化学演化有很大的影响。实验室工作将包括一系列精确控制和监测的流动槽研究，旨在描述混合过程的动力学。实地研究将包括对Milk河含水层的地质和水文地质进行详细描述，然后用变密度模型进行评估。这项研究将为一个相对未知和知之甚少的过程提供基本知识。先前的研究表明，不稳定发展引起的混合可能比通常认识到的更为重要。该研究对溶剂增强采油、沉积盆地化学混合、污染物运移等问题具有重要的理论和实践意义。

This is a three-year experimental, theoretical and field study of convective instability and its role in solute mixing during mass transport. Instabilities can develop at different scales under a variety of geologic and hydrogeologic situations when more dense groundwater overlies less dense groundwater. The process mixes the two waters to reduce the density stratification. The specific objectives of the study are to describe the dynamics of instability development both conceptually and mathematically and to evaluate the potential for instability development to influence the chemical evolution of groundwater in large flow systems. The study includes both experiments and the evaluation of an actual groundwater system, the Milk River artesian aquifer, in which unstable mixing has a significant potential for influencing the chemical evolution of the water. The laboratory work will involve a series of precisely controlled and monitored flow tank studies designed to describe the dynamics of the mixing process. The field study will involve a detailed characterization of the geology and hydrogeology of the Milk River aquifer, followed by an evaluation with a variable density model. This study will contribute basic knowledge about a relatively unknown and poorly understood process. Previous studies show that mixing due to instability development can be more important than commonly realized. The work is of practical and academic importance to problems of solvent-enhanced oil recovery, chemical mixing in sedimentary basins and contaminant migration.