Collaborative Research: IDR-Model-based Feedback Control of Transient Growth in a Laminar Boundary Layer: Bridging the Gap between CFD and Experiments

这个研究奖项的目的是消除或削弱在线性阶段的干扰粗糙度引起的瞬态增长。这项合作研究的动机是对扰动瞬态增长的反馈控制，这些扰动会导致边界层在粗糙表面上或湍流自由流下从层流状态转变为湍流状态。特别是，该研究旨在解决基于紧密耦合实验和计算的基于模型的Blasius边界层瞬态生长反馈控制路径上的开放基本挑战。控制的基础是基于平衡固有正交分解（BPOD）和特征系统实现算法（ERA），结合壁面剪切应力传感器阵列和等离子体作动器，对流体动力学方程进行平衡截断低阶动力学建模。本研究涉及流体动力学、反馈控制和动力系统等多学科。这项研究的直接影响将是通过实验证明基于降阶流量估计、控制方程建模和分布式传感和驱动的多模态、旁路过渡反馈控制。如果研究成功，将对节能环保的工程应用产生重大影响。这些包括但不限于运输系统、推进和发电系统以及长管道。这项研究将教育博士生，让本科生参与研究，并扩展到K-12学生。

The objective of this research award is the elimination or weakening of disturbances during the linear stage of roughness-induced transient growth.This collaborative research is motivated by feedback control of the transient growth of disturbances that cause the boundary layer to transition from a laminar to turbulent state over a rough surface or beneath a turbulent freestream. In particular, the research seeks to address open fundamental challenges in the path of attaining model-based feedback control of transient growth in a Blasius boundary layer based on closely coupled experiments and computations. The basis for the control is balanced-truncation low-order dynamical modeling of the fluid dynamics equations based on Balanced Proper Orthogonal Decomposition (BPOD) and eigensystem realization algorithm (ERA) coupled with arrays of wall-shear-stress sensors and plasma actuators. This research is multidisciplinary involving fluid dynamics, feedback control and dynamical systems. The direct impact of this research will be to experimentally demonstrate multi-modal, bypass-transition feedback control based on reduced-order flow estimation, modeling of the governing equations and distributed sensing and actuation. If successful the proposed research will have significant impact on energy conservation and environmental protection in a host of engineering applications. These include, but are not limited to, transport systems, propulsion and power generation systems, and long pipe lines. This study will educate Ph.D. students, involve undergraduate students in research, and outreach to K-12 students.