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减弱粗糙引起的瞬时增长线性阶段的扰动。这项合作研究的动机是对扰动的瞬时增长进行反馈控制，这些扰动导致边界层在粗糙表面或湍流自由流下从层流过渡到湍流状态。特别是，这项研究试图解决在基于紧密耦合的实验和计算的Blasius边界层中实现基于模型的瞬时增长的反馈控制的道路上的开放的基本挑战。控制的基础是基于平衡本征正交分解(BPOD)和特征系统实现算法(ERA)的流体动力学方程的平衡截断低阶动态建模，并结合壁面剪应力传感器和等离子体执行器阵列。本研究涉及流体力学、反馈控制和动力系统等多个学科。这项研究的直接影响将是在实验上演示基于降阶流量估计、控制方程建模以及分布式传感和执行的多模式旁路过渡反馈控制。如果研究成功，将对节能环保等一系列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，并扩大到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.