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

该研究奖的目标是消除或削弱粗糙度引起的瞬态增长的线性阶段的扰动。该合作研究的动机是对扰动的瞬态增长进行反馈控制，这些扰动导致边界层在粗糙表面上或湍流自由表面下从层流过渡到湍流状态。特别是，该研究旨在解决开放的基本挑战的路径上实现基于模型的反馈控制的瞬态增长的Blasius边界层的基础上紧密耦合的实验和计算。 控制的基础是平衡截断低阶动力学模型的流体动力学方程的基础上平衡本征正交分解（BPOD）和特征系统实现算法（ERA）耦合阵列的壁面剪应力传感器和等离子体致动器。该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实验证明多模态，旁路过渡反馈控制的基础上降阶流量估计，建模的控制方程和分布式传感和驱动。如果该研究取得成功，将在许多工程应用中对节能和环境保护产生重大影响。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。学生，让本科生参与研究，并推广到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.