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

湍流在自然和工程的一系列重要领域中发挥着至关重要的作用，从气候到航空到心血管疾病。特别是，湍流是工程中最重要的现象之一，因为湍流对各种设计系统（如汽车和航空航天工业）的流动阻力负有重要责任。然而，尽管湍流具有重要的意义，并且几十年来的研究都集中在控制这些流动以节省能源上，但由于湍流的混沌性质，湍流控制在科学上仍然具有挑战性。本项目将探讨湍流的混沌本质，前提是基于统计随机性的流行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备的实验技术相结合。这种系统的协作方法将被用于改变对湍流的理解，从而开辟大量节约能源的可能性。该项目将建立PI所在的内布拉斯加大学林肯分校和明尼苏达大学之间的长期合作关系，以推进对湍流的基本理解。技术描述湍流在自然界中无处不在，被认为是经典物理和数学中最大的未解决问题。此外，湍流是工程中最重要的现象之一，因为湍流对阻力的影响很大，而阻力与能量消耗直接相关。然而，由于湍流的随机性，控制湍流一直是一个难以克服的挑战。本研究的目标是推进一个发现和预测高度有组织的湍流动力学的第一性原理系统框架，其长期目标是利用这个框架来改善湍流控制，提高许多流动过程的能量效率。目标是建立在紊流动力学理解的最新进展上，找到并利用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有组织的湍流动力学，与明尼苏达大学的一个团队合作，该大学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、完善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分校的设施，以维持长期的研究工作。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.