CAREER: Unraveling predictive and multiscale dynamics in turbulence for flow control

职业：揭示湍流中流动控制的预测和多尺度动力学

• 批准号: 2142916
• 负责人: Jae Sung Park
• 金额: $ 50.68万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2026-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2142916&HistoricalAwards=false
• 关键词: CAREER; Unraveling; predictive; multiscale; dynamics

Turbulent flow plays a crucial role in health and engineering across a range of important issues, from climate to aviation and cardiovascular disease. A better understanding of turbulence is thus central to human health and the sustainability of natural resources. The most essential features of turbulence are its chaotic and multiscale natures, posing both challenges and opportunities. To address this challenge, the principal aim of this project is to provide a new theoretical and computational research avenue that uses a deterministic framework to unravel predictable and multiscale characteristics in turbulence for flow control. In addition to providing the fundamental knowledge necessary to advance energy-saving flow-control strategies, this project will also provide the perfect educational platform to promote practical workforce training in academia as the real-world importance of turbulence and flow control will excite students at various levels. To this end, industry-relevant projects will be developed to cultivate a highly qualified industrial workforce by bridging the gap between academic work and industrial problems.The goal of this project is to apply recent advances in the dynamical systems viewpoint of turbulence to solve the problem of the chaotic and multiscale nature embedded in turbulence for rigorous flow control. The key idea is to uncover the predictability and multiscale interactions in turbulence using so-called exact coherent solutions to the governing Navier-Stokes equations. The new knowledge obtained will be exploited for cost-effective turbulence control. In pursuit of this goal, the specific objectives are: (i) identify the predictive dynamics using small-scale exact coherent solutions and (ii) characterize the multiscale interactions between small-scale and large-scale exact coherent solutions and exploit them for flow control. Direct numerical simulation and large-eddy simulation will be employed to simulate and analyze small-scale and large-scale exact coherent solutions, respectively, along with a suite of analysis tools, including linear instability analysis and resolvent analysis. The discovery that predictive and multiscale dynamics exist will lead to a more rigorous control strategy that can steer turbulence toward desirable states, whereby targeted larger scales are controlled by controlling smaller ones. As energy losses in various industrial flow systems are largely associated with turbulent drag, this project has far-reaching implications in effectively improving the energy efficiency of the systems by taking full advantage of the predictive and multiscale dynamics in turbulence.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.

湍流在从气候到航空和心血管疾病等一系列重要问题的健康和工程中发挥着至关重要的作用。因此，更好地了解湍流对人类健康和自然资源的可持续性至关重要。动荡的最本质特征是其无序性和多尺度性质，既带来挑战，也带来机遇。为了应对这一挑战，该项目的主要目标是提供一种新的理论和计算研究途径，使用确定性框架来揭示湍流中可预测的多尺度特征，以进行流动控制。除了提供推进节能流量控制策略所需的基本知识外，该项目还将提供完美的教育平台，以促进学术界的实际劳动力培训，因为湍流和流量控制在现实世界中的重要性将激发不同水平的学生。为此，将开发与行业相关的项目，通过弥合学术工作和工业问题之间的差距来培养高素质的工业劳动力。该项目的目标是应用湍流动力系统观点的最新进展来解决湍流中嵌入的混沌和多尺度性质的问题，以实现严格的流动控制。其核心思想是使用控制的Navier-Stokes方程的所谓精确相干解来揭示湍流中的可预测性和多尺度相互作用。所获得的新知识将被用于具有成本效益的湍流控制。为了实现这一目标，具体目标是：(I)使用小尺度精确相干解来识别预测动力学；(Ii)表征小尺度精确相干解与大尺度精确相干解之间的多尺度相互作用，并将其用于流量控制。采用直接数值模拟和大涡模拟的方法，分别模拟和分析小尺度和大尺度的精确相干解，并使用一套分析工具，包括线性不稳定性分析和预解分析。预测和多尺度动力学的发现将导致一种更严格的控制策略，可以将湍流引导到理想的状态，从而通过控制较小的尺度来控制目标较大的尺度。由于各种工业流动系统中的能量损失在很大程度上与湍流阻力有关，该项目对充分利用湍流中的预测性和多尺度动力学有效地提高系统的能源效率具有深远的影响。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-to-Turbulent Transition in a Wall-Bounded Channel Flow Up to Re=40,000

Re=40,000 以下的壁限通道流中层流到湍流转变的动力学

• DOI: 10.1115/imece2022-94489
• 发表时间: 2022
• 期刊: Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition
• 作者: Al Barwani, Mohsin;Park, Jae Sung
• 通讯作者: Park, Jae Sung