Molecular Tagging Techniques for Stratified Flow: Application to Boundary Mixing

热、盐和污染物的迁移对于测量和预测环境流是重要的。例如，湖泊的水质取决于热量和污染物的垂直传输，海洋中热量和盐的传输影响全球气候。为了提高测量和建模的运输，分子标记测速和测温（MTV T），这已成功地应用于其他工程流，将扩展到分层流中使用。该技术将被应用于一个实验室模型的混合内波驱动的边界湖泊和海洋。该项目的具体目标是（1）扩展MTV T盐分层流，（2）量化湍流和混合所产生的长波，和（3）确定间歇强迫的混合和transmitt.The拟议的研究的智力价值来自于能够测量的混合和湍流在边界层所产生的内波比以前更详细; MTV T将提供二维领域的速度，浓度和通量，同时避免了其他技术的一些陷阱。拟议的实验室实验开始一个经过充分研究的情况下，以验证分子标记技术，然后扩展以前的实验室工作，研究其他因素，是重要的解释现场测量。同时进行的现场测量将指导实验室实验的设计，并测试实验室的结果。拟议中的工作利用PI Pirammann的测量和建模的边界混合和PI胡？在先进的流量测量和可视化技术方面的专业知识。更广泛的影响包括培训研究生，对学校进行推广，并将分子标记方法应用于分层流。这项推广活动利用了赫尔曼和胡锦涛与爱荷华州学校和项目建立的联系，以扩大代表性不足的群体的参与。此外，拟议中的项目涉及的分子标记方法的第一个应用程序的分层流的环境的重要性，因为以前的现场测量表明，边界混合可以控制流域范围内的垂直运输在湖泊和海洋，这些实验将提供有价值的信息建模污染物在环境中的传输。此外，一旦拟议的工作证明分子标记对于边界混合的有用性，它就可以用于环境中许多其他分层流的实验室模型中。

1067270RehmannThe transport of heat, salt, and contaminants is important to measure and predict in environmental flows. For example, water quality in lakes depends on vertical transport of heat and contaminants, and the transport of heat and salt in the ocean affects the global climate. To improve the measurement and modeling of transport, molecular tagging velocimetry and thermometry (MTV&T), which has been applied successfully in other engineering flows, will be extended for use in stratified flows. The technique will be applied in a laboratory model of mixing driven by internal waves at the boundary of lakes and oceans. Specific objectives of the project are to (1) extend MTV&T to salt-stratified flow, (2) quantify turbulence and mixing generated by long waves, and (3) determine the effect of intermittent forcing on the mixing and transport.The intellectual merit of the proposed research comes from the ability to measure the mixing and turbulence in a boundary layer generated by internal waves in more detail than previously possible; MTV&T will provide two-dimensional fields of velocity, concentration, and flux while avoiding some of the pitfalls of other techniques. The proposed laboratory experiments start with a well-studied case to verify the molecular tagging technique and then extend previous laboratory work to study other factors that are important in interpreting field measurements. Concurrent field measurements will guide the design of the laboratory experiments and test the results from the lab. The proposed work exploits PI Rehmann's experience with measurements and modeling of boundary mixing and PI Hu?s expertise in advanced flow measurement and visualization techniques. The broader impacts include training a graduate student, conducting outreach to schools, and applying molecular tagging methods to stratified flow. The outreach uses the connections that Rehmann and Hu have established with Iowa schools and programs to broaden the participation of underrepresented groups. Also, the proposed project involves the first application of the molecular tagging method to a stratified flow of environmental importance; because previous field measurements have shown that boundary mixing can control the basin-wide vertical transport in lakes and oceans, these experiments will provide valuable information for modeling contaminant transport in the environment. Furthermore, once the proposed work demonstrates the usefulness of molecular tagging for boundary mixing, it can be used in laboratory models of many other stratified flows in the environment.