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.
