Characterization of Turbulent Flow in Porous Media: Integrating Experiments, DNS, and Theory

1336983木材拟议研究的主要目标是研究多孔介质中的快速(高雷诺数)流动。提出了一种统一的方法，它集成了三个研究元素(1)带有闭合的升标理论(体积平均法)，(2)多孔介质中流动的直接数值模拟(DNS)，(3)多孔介质中流动的PIV实验研究。这项研究将涵盖大范围的雷诺数[Re~O(100-4000)]。这项工作的总体目标是提供一个内聚性理论(经过广泛的实验验证)来描述填充床中相当高的速度流动，其方式与广泛使用的达西-埃尔贡-福奇海默方程的经验表达式一致。高Re流动在多孔介质中的广泛应用包括固定床反应堆、核反应堆和地下水修复中的气体吸附、过滤、催化剂反应、燃烧、热传输等过程。由于孔隙空间内复杂和不规则的流动结构、流动的限制因素和可变长度的尺度，很难正确地定义多孔材料中高Re流动的平均流动结构和相关的湍流。这些同样的复杂性使得实验观测和数值模拟变得极其困难。到目前为止，对于随机堆积的多孔介质中的湍流流动，很少有详细的PIV或DNS数据，也没有一种数据能在DNS和实验之间交叉验证。拟议的研究汇集了实验、计算和理论方法方面独特和互补的专业知识和能力。我们将结合实验和模拟数据来加深我们对多孔材料中流动物理的理解。这一方法将致力于提供一致的理论，有可能改变稠密堆积多孔介质中热量或标量传输的建模方法。实验将使用三分量时间分辨粒子图像测速仪对简单立方体填充和随机填充的多孔珠的孔隙尺度速度场数据进行测量。域名系统的工作将集中在定常/非定常惯性、过渡和湍流的高保真、全分辨直接数值模拟。这两个来源的详细数据将阐明所需的复杂的流动结构和湍流特性，以形成开发宏观流动和输运特性预测工具的理论基础。具体地说，这些数据将有助于直接评估由于模型中未解决的亚格子运动尺度而导致的非线性封闭项。研究计划将成为培训学生的基础，并帮助他们认识到对复杂问题进行必要的综合分析的必要性。私人投资机构有在其实验室中吸收代表性不足的群体的记录，包括研究生和本科生(如德事隆学者[向一年级女性提供]和大学荣誉学生)。这个项目将接触到发展中的工程师，通过OSU-微笑指导计划为中学生提供学习机会(该计划针对的是代表性不足的群体)。通过与图卢兹的Mecanique des Fluids de Toulouse学院的合作，也将向学生提供国际接触。此外，研究生将通过拟议的补助金和部门资金得到支助，以便在国际和国家会议上介绍他们的工作。研究人员将在最后一年计划在国际会议(如AGU)上举行两次特别会议。该项目由化学、生物工程、环境和运输系统部门的流体动力学和颗粒和多相过程计划联合资助。

1336983WoodThe primary objective of the proposed research is to examine fast (high Reynolds number) flows in porous media. A unified approach is proposed, which integrates three research elements (1) upscaling theory (the method of volume-averaging ) with closure, (2) direct numerical simulation (DNS) of flow in porous media, and (3) PIV experimental studies of flows in porous media. The study will cover a broad range of Reynolds numbers [Re ~O(100-4000)]. The overall goal of this work is to provide a cohesive theory (with extensive experimental validation) to describe rather high velocity flows in a packed bed in a way that is consistent with the widely-used empirical expression known as the Darcy-Ergun-Forchheimer equation. The wide range of applications of high Re flows in porous media includes gas adsorption, filtration, catalyst reactions, combustion, heat transport and other processes in fixed bed reactors, nuclear reactors and subsurface groundwater remediation. Due to the complex and irregular flow geometry within the pore space, the confining aspects of the flow, and the variable length scales, it is difficult to properly define the mean flow structure and associated turbulence of high Re flows in porous materials. These same complexities make experimental observations and numerical simulations extremely difficult. To date there exist few detailed PIV or DNS data for turbulent flows in randomly packed porous media, and none that cross validate among DNS and experiment. The proposed research brings together unique and complementary expertise and capabilities in experimental, computational, and theoretical approaches. Combined experiments and simulation data will be used to enhance our understanding of the flow physics in porous materials. The upscaling approach, which will focus on providing a consistent theory, has the potential to transform modeling approaches for heat or scalar transport in densely packed porous media. The experiments will involve pore-scale velocity field data for both simple cubic packing and randomly packed porous beads using three-component time-resolved particle image velocimetry. The DNS work will focus on high-fidelity, fully resolved direct numerical simulations of steady/unsteady inertial, transitional and turbulent flows. The detailed data from both sources will elucidate the complex flow structures and turbulence characteristics needed to form a theoretical basis for the development of a predictive tool for macroscopic flow and transport properties in porous media. Specifically, the data will facilitate direct evaluation of non-linear, closure terms due to unresolved, sub-grid scales of motion in the model.The research plan will become the basis for training students and helping them appreciate the need for the integrated analysis necessary for complex problems. The PIs have a track record of involving underrepresented groups in their laboratories, both graduate and undergraduates (such as Textronic Scholars [available to first-year women] and University Honors Students. This project will reach out to developing engineers to provide a learning opportunity through the OSU-SMILE mentoring program for middle school students (which targets underrepresented groups). International exposure through collaborations with Insitut de Mecanique des Fluides de Toulouse will also be available to students. In addition the graduate students will be supported through the proposed grant and departmental funds to present their work at international and national conferences. The investigators will plan two special sessions at international conferences (such as AGU) during the final year.This project is jointly funded by the Fluid Dynamics and Particulate and Multiphase Processes Programs in Chemical, Bioengineering, Environmental, and Transport Systems Division.