Abstract
Transient energy growth of flow perturbations is an important mechanism for laminar-to-turbulent transition that can be mitigated with feedback control. Linear quadratic optimal control strategies have shown some success in reducing transient energy growth and suppressing transition, but acceptable worst-case performance can be difficult to achieve using sensor-based output feedback control. In this study, we investigate static output feedback controllers for reducing transient energy growth of flow perturbations within linear and nonlinear simulations of a subcritical channel flow. A static output feedback linear quadratic regulator (SOF-LQR) is designed to reduce the worst-case transient energy growth due to flow perturbations. The controller directly uses wall-based measurements to optimally regulate the flow with wall-normal blowing and suction from the upper and lower channel walls. We show that SOF-LQR controllers can reduce the worst-case transient energy growth of flow perturbations. Our results also indicate that SOF-LQR controllers exhibit robustness to Reynolds number variations. Further, direct numerical simulations show that the designed SOF-LQR controllers increase laminar-to-turbulent transition thresholds under streamwise disturbances and delay transition under spanwise disturbances. The results of this study highlight the advantages of SOF-LQR controllers and create opportunities for realizing improved transition control strategies in the future.
Original language | English (US) |
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Pages (from-to) | 4039-4052 |
Number of pages | 14 |
Journal | AIAA journal |
Volume | 60 |
Issue number | 7 |
DOIs | |
State | Published - 2022 |
Externally published | Yes |
ASJC Scopus subject areas
- Aerospace Engineering