RII Track-4: Finding Order in Chaos: a Systematic Approach to Turbulence Control for Drag Reduction

RII Track-4：在混沌中寻找秩序：减少阻力的湍流控制的系统方法

• 批准号: 1832976
• 负责人: Jae Sung Park
• 金额: $ 17.74万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-10-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1832976&HistoricalAwards=false
• 关键词: RII; Track; Finding; Order; Chaos

Nontechnical DescriptionTurbulent flows play a crucial role in nature and engineering across a range of important areas, from climate to aviation to cardiovascular disease. In particular, turbulence is one of the most important phenomena in engineering because turbulent flows are significantly responsible for flow resistance in various designed systems such as in the automotive and aerospace industries. However, despite the critical implications of turbulent flows and decades of research focused on controlling these flows for energy savings, turbulence control is still scientifically challenging due to the chaotic nature of turbulence. This project will probe the chaotic nature of turbulence, on the premise that prevailing theories based on statistical randomness are conceptual barriers to future breakthroughs. To this end, the PI's mathematical and computational methods will be integrated with experimental techniques using state-of-art facilities at the University of Minnesota. This systematic collaborative approach will be employed to transform understanding of turbulent flows, opening up the possibility of substantial energy savings. This project will establish a long-term collaboration between the PI's home institution of the University of Nebraska-Lincoln and the University of Minnesota to advance the fundamental understanding of turbulent flows.Technical DescriptionUbiquitous in nature, turbulence is regarded as the greatest unsolved problem in classical physics and mathematics. In addition, turbulence is one of the most important phenomena in engineering because turbulent flows are significantly responsible for drag, which is directly related to energy consumption. However, controlling turbulence has thus far been an insurmountable challenge due to the random characteristic nature of turbulent flows. The goal of this research is to advance a first-principles systematic framework for discovering and predicting highly organized turbulent dynamics, with a longer-term goal of exploiting this framework for improved turbulence control and increased energy efficiency in many flow processes. The objective is to build on recent advances in the dynamical understanding of turbulent flows to find and exploit a predictive model for rigorous flow control. The research takes a systematic approach to transform our understanding of turbulence. The PI will use a computational and mathematical framework to characterize organized turbulent dynamics between the ordered flow structures, working in collaboration with a team at the University of Minnesota whose facilities provide an excellent research environment for experimental validations of the ordered flow structures and the predictive model. The PI will utilize, refine, and further develop a systematic approach to discover a predictive model of turbulent flows, identifying evidence of organized turbulent dynamics. Ultimately, the PI will utilize knowledge gained during the fellowship to improve and develop facilities at the University of Nebraska-Lincoln to sustain a long-term research effort.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述湍流在从气候到航空再到心血管疾病等一系列重要领域的自然和工程中发挥着至关重要的作用。特别是，湍流是工程中最重要的现象之一，因为在汽车和航空航天工业等各种设计的系统中，湍流对流动阻力起着重要的作用。然而，尽管湍流的重要影响和几十年来专注于控制这些流动以节省能源的研究，由于湍流的混沌性质，湍流控制仍然是科学上的挑战。这个项目将探索湍流的混乱本质，前提是基于统计随机性的主流理论是未来突破的概念障碍。为此，PI的数学和计算方法将与使用明尼苏达大学最先进设施的实验技术相结合。这种系统的协作方法将被用来改变对湍流的理解，从而打开了大量节省能源的可能性。该项目将在PI的家乡机构内布拉斯加-林肯大学和明尼苏达大学之间建立长期的合作关系，以促进对湍流的基本理解。湍流在自然界中普遍存在，被认为是经典物理和数学中最大的悬而未决的问题。此外，湍流是工程中最重要的现象之一，因为湍流对阻力有很大的影响，而阻力与能源消耗直接相关。然而，由于湍流的随机特性，控制湍流到目前为止一直是一个不可逾越的挑战。这项研究的目标是提出一个发现和预测高度组织化的湍流动力学的第一原理系统框架，长期目标是利用这个框架在许多流动过程中改善湍流控制和提高能源效率。其目的是建立在湍流动力学理解的最新进展的基础上，找到并开发用于严格流动控制的预测模型。这项研究采用了一种系统的方法来改变我们对湍流的理解。PI将使用计算和数学框架来表征有序流动结构之间的有组织的湍流动力学，与明尼苏达大学的一个团队合作，该团队的设施为有序流动结构和预测模型的实验验证提供了良好的研究环境。PI将利用、改进和进一步发展一种系统的方法来发现湍流的预测模型，识别有组织的湍流动力学的证据。最终，PI将利用在奖学金期间获得的知识来改善和发展内布拉斯加大学林肯大学的设施，以维持长期的研究努力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Dynamics of laminar and transitional flows over slip surfaces: effects on the laminar–turbulent separatrix

• DOI: 10.1017/jfm.2020.282
• 发表时间: 2020-04
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: Ethan A. Davis;J. S. Park

On the Comparison of Flow Physics between Minimal and Extended Flow Units in Turbulent Channels

• DOI: 10.3390/fluids6050192
• 发表时间: 2021-05
• 期刊: Fluids
• 影响因子: 1.9
• 作者: Ethan A. Davis;S. Mirfendereski;J. S. Park

On the Underlying Drag-Reduction Mechanisms of Flow-Control Strategies in a Transitional Channel Flow: Temporal Approach

过渡河道流中流量控制策略的潜在减阻机制：时间方法

• DOI: 10.1007/s10494-021-00305-7
• 发表时间: 2022
• 期刊: Turbulence and Combustion
• 作者: Rogge, Alexander J.;Park, Jae Sung
• 通讯作者: Park, Jae Sung

Wall-Shear-Stress-Based Conditional Sampling Analysis of Coherent Structures in a Turbulent Boundary Layer

• DOI: 10.1115/1.4049403
• 发表时间: 2021-04
• 期刊: Journal of Fluids Engineering-transactions of The Asme
• 影响因子: 2
• 作者: Sangjin Ryu;Ethan A. Davis;J. S. Park;Haipeng Zhang;J. Yoo