Rod Dynamics in Turbulence: Simultaneous 3D measurements of Anisotropic Particles and Velocity Fields

湍流中的杆动力学：各向异性粒子和速度场的同步 3D 测量

• 批准号: 1208990
• 负责人: Greg Voth
• 金额: $ 33万
• 依托单位: Wesleyan University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1208990&HistoricalAwards=false
• 关键词: Rod; Dynamics; Turbulence; Simultaneous; 3D

****Technical Abstract****In a wide range of natural and industrial situations, turbulent flows carry particulate material. As such, the dynamics of turbulent suspensions and aerosols has been an active area of research. Significant progress has been made in characterizing the motion of spherical particles in turbulence; much less is known, however, about the dynamics of anisotropic particles. The rotation of anisotropic particles is determined by small scale properties of turbulence that are nearly universal across a wide range of flows, and so anisotropic particles provide a rich system where experiments can be directly compared with theory and simulations. The research proposed here will provide the first high-resolution experimental measurements of the 3D dynamics of rod shaped particles in turbulence. We will then extend these measurements to anisotropic objects across the full range of aspect ratios from rods to isotropic particles to disks. We will also implement a recently developed measurement system that will allow extremely high seeding densities necessary to measure the velocity gradients of the flow simultaneously with measurements of rod motion. This will allow measurement of the stretching experienced by the particle along its trajectory which is the fundamental quantity responsible for preferential alignment of anisotropic particles. Education and research training are central to this project, which will support the mentoring of undergraduates, graduate students, and a postdoctoral scientist, as well as training K-12 educators in physical science.****Non-Technical Abstract****In a wide range of natural and industrial situations, turbulent flows carry particulate material. For example, clouds are turbulent flows containing water droplets and ice crystals. Papermaking uses turbulent suspensions of fibers. If the particles are spheres, there are a variety of tools available for measuring their motion. But usually the particles are not spheres, and the movement and rotations of non-spherical particles have never before been measured as they are carried by a turbulent flow. This project will develop experimental tools to make these measurements. Particle rotations are of particular interest because their statistics are expected to be similar in all turbulent flows, and measurements can be compared with theoretical predictions for the universal properties of turbulence. This work seeks to establish a clear understanding of the fundamental characteristics of non-spherical particle motion in laboratory turbulent flows that can be used to understand more complex applications such as icy clouds and papermaking. Education and research training are central to this project, which will support the mentoring of undergraduates, graduate students, and a postdoctoral scientist, as well as training K-12 educators in physical science.

* 技术摘要 * 在广泛的自然和工业情况下，湍流携带颗粒材料。因此，湍流悬浮物和气溶胶的动力学一直是一个活跃的研究领域。在描述球形粒子在湍流中的运动方面已经取得了重大进展，但是对各向异性粒子的动力学知之甚少。 各向异性颗粒的旋转由湍流的小尺度特性决定，这些特性在很宽的流动范围内几乎是普遍的，因此各向异性颗粒提供了一个丰富的系统，可以直接将实验与理论和模拟进行比较。 这里提出的研究将提供第一个高分辨率的实验测量的三维动力学的棒状颗粒在湍流。 然后，我们将这些测量扩展到各向异性的物体在整个范围内的纵横比，从棒到各向同性粒子磁盘。 我们还将实施一个最近开发的测量系统，这将允许极高的播种密度，同时测量棒运动的测量流量的速度梯度。 这将允许测量颗粒沿着其轨迹所经历的拉伸，该拉伸是负责各向异性颗粒的优先排列的基本量。教育和研究培训是该项目的核心，该项目将支持本科生，研究生和博士后科学家的指导，以及培训K-12教育工作者的物理科学。非技术摘要 * 在广泛的自然和工业情况下，湍流携带颗粒材料。 例如，云是包含水滴和冰晶的湍流。 造纸使用纤维的湍流悬浮液。 如果粒子是球体，有各种工具可用于测量它们的运动。 但通常颗粒不是球体，并且非球形颗粒的运动和旋转以前从未被测量过，因为它们被湍流携带。 该项目将开发进行这些测量的实验工具。 粒子旋转是特别感兴趣的，因为它们的统计数据预计在所有湍流中是相似的，并且可以将测量结果与湍流普适性质的理论预测进行比较。 这项工作旨在建立一个清晰的理解，非球形粒子运动的基本特征，在实验室湍流，可用于了解更复杂的应用，如冰云和造纸。 教育和研究培训是这个项目的核心，它将支持本科生，研究生和博士后科学家的指导，以及培训K-12教育工作者在物理科学。