Coherent Structures and Mixing in Rotating and Stratified Flows

这是一个探索和模拟导致湍流混合的湍流结构的建议。这项工作将集中在各向异性湍流的情况下，这一领域还没有像其他湍流那样被探索，但在工程和环境中具有极其重要的意义。在这项工作中提出的研究涵盖了多种尺度的计算，甚至与地球物理流动相关的尺度，使得结果不仅因为湍流混合的基本方面，而且由于在实际情况中的适用性而有用。我们的气候、农业和商业都受到大气和海洋湍流的影响。这项工作可能会产生更准确的海洋和大气流动模型，对政策、经济和基础设施决策产生影响。生成的数据将通过已建立的约翰霍普金斯大学湍流数据库提供给科学界。此外，研究生将参与该项目。提出的研究的目的是调查旋转和分层效应以及不同混合动力学在湍流中活跃的尺度。PI建议使用最先进的直接数值模拟（DNS）代码，并使用相当可观的计算资源（可通过美国能源部科学办公室的拨款获得）运行几个大型计算。提出的工作旨在通过以下方式推进我们对湍流混合的基本理解：1)用统计方法表征和量化在典型旋转和分层流动中形成的相干结构的内在尺度；2)量化尺度之间的关系，从而恢复到统计和混合的内在尺度。

This is a proposal to explore and model the structure of turbulence that leads to mixing in turbulent flows. The work will focus on cases of anisotropic turbulence, an area that has not been explored as much as other turbulent flows, but is of the utmost importance in engineering and in the environment. The research proposed in this work covers computations at a multitude of scales, even scales relevant to geophysical flows, allowing the results to be useful not only because of the fundamental aspect of turbulent mixing, but also due to applicability in practical situations. Our climate, agriculture, and commerce are affected by turbulence in the atmosphere and in the ocean. This work could lead to more accurate models for ocean and atmospheric flows with impact on policy, economic and infrastructure decision. The data that will be generated will become available to the scientific community through the established Johns Hopkins University Turbulence Database. In addition, graduate students will participate in this project. The goal of the proposed study is to investigate rotation and stratification effects and the scales at which different mixing dynamics are active in a turbulent flow. The PI proposes to use state-of-the-art direct numerical simulations (DNS) code and to run several large calculations using computational resources that are quite impressive (available through allocations from the DOE Office of Science). The proposed work aims to advance our fundamental understanding of turbulent mixing by, 1) characterizing and quantifying the instrinsic scales of coherent structures formed in canonical rotating and stratified flows using statistical measures and, 2) quantifying the relationship of the scales thus recovered to the statistics and the instrinsic scales of mixing.