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CAREER: Controlling Nonlinear Flow Interactions to Suppress Transition to Turbulence

职业：控制非线性流动相互作用以抑制向湍流的转变

基本信息

批准号：
1943988
负责人：
Maziar Hemati
金额：
$ 50万
依托单位：
University of Minnesota-Twin Cities
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-01-01 至 2024-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1943988&HistoricalAwards=false
关键词：
CAREER Controlling Nonlinear Flow Interactions

项目摘要

In a wide range of engineering systems (e.g., airplanes, cars, pipelines, and wind turbines), delaying transition of flow from laminar to turbulent can lead to reduced drag and improved efficiency. The research will study complex (nonlinear) flow interactions that will suppress laminar transition to turbulence and achieve drag reduction. Computer simulations of a channel flow incorporating only wall-based sensing and actuation of the flow will be used to demonstrate the delays in transition. The effort closely integrates education and outreach with foundational research that enhances interdisciplinary fluid dynamics, systems modeling, and control theory. The multidisciplinary work will be disseminated to the fluids, dynamical systems, and controls communities to enhance communication between these disciplines. Newly developed courses and undergraduate research initiatives will promote higher education in engineering. A new outreach program will help elementary school teachers introduce engineering into K-6 classrooms.Nonlinear flow interactions are at the heart of the transition process. Yet, previous studies on transition control have focused on the pre-nonlinear interaction stage and have not exploited a complete description of these interactions for controller synthesis. The proposed effort hinges on the fact that nonlinear flow interactions are dynamically constrained by the Navier-Stokes equations, both at a given time instant and across time instances. Mathematically, these physical constraints can be expressed as a set of integral quadratic constraints, providing a convenient framework for modeling nonlinear flow interactions for transition control synthesis. This project seeks to determine how such representations of nonlinear flow interactions can be exploited to suppress transition within direct numerical simulations of a channel flow, using only wall-based sensing and actuation. The outcomes of this project will provide guidance on how to formally account for nonlinear flow interactions to perform flow control, sensor selection, and model-order reduction in a manner that can be generalized to many complex flow configurations.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.

在广泛的工程系统中(如飞机、汽车、管道和风力涡轮机)，延迟流动从层流到湍流的转变可以减少阻力并提高效率。这项研究将研究复杂的(非线性)流动相互作用，这种相互作用将抑制层流向湍流的转变，并实现减阻。计算机模拟的渠道流只包含基于墙的传感和驱动的流动将被用来演示在过渡过程中的延迟。这项工作将教育和推广与基础研究紧密结合起来，加强跨学科的流体动力学、系统建模和控制理论。这项多学科的工作将传播到流体、动力系统和控制社区，以加强这些学科之间的沟通。新开发的课程和本科研究计划将促进高等工程教育。一项新的推广计划将帮助小学教师将工程学引入K-6课堂。非线性流动互动是过渡过程的核心。然而，以往对过渡控制的研究主要集中在前非线性交互作用阶段，而没有对这些交互作用进行完整的描述来进行控制器综合。所提出的努力取决于这样一个事实，即非线性流动相互作用在给定的时刻和跨时间实例都受到Navier-Stokes方程的动态约束。在数学上，这些物理约束可以表示为一组积分二次约束，为过渡控制综合中的非线性流动交互建模提供了一个方便的框架。这个项目试图确定如何利用这种非线性流动相互作用的表示法来抑制渠道流的直接数值模拟中的过渡，只使用基于墙的传感和激励。该项目的成果将为如何正式解释非线性流动相互作用以执行流量控制、传感器选择和模型降阶提供指导，这种方式可以推广到许多复杂的流动结构。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。