Real-Time Adaptive Feedback Control of a Supersonic Dual-Stream Jet

TL;DR

This paper presents a real-time adaptive feedback control method for suppressing resonant tones in a supersonic dual-stream jet flow using online dynamic mode decomposition and constrained control models.

Contribution

It introduces an efficient, sensor-agnostic adaptive control framework that suppresses flow tones and shock trains in supersonic jets with physical and practical constraints.

Findings

Adaptive control effectively suppresses the resonant tone.

The control framework is robust to sensor placement.

Suppression of low-pressure events reduces flow instability.

Abstract

Adaptive control is applied to a supersonic dual-stream jet flow comprised of Mach 1.6 core and Mach 1.0 bypass streams that mix to form a supersonic shear layer. The vortices shed are the source of a high-frequency tone that persists throughout the flow. The intricate flow dynamics motivates the need for an elaborate and efficient actuation system to suppress the tone and weaken the propagating shock train. The present work utilizes online dynamic mode decomposition, which estimates the system dynamics as a locally linear evolution. Snapshot matrices are constructed using sensor measurements, facilitating economical and real-time computations, which are continuously updated and used in a feedback control model. Adaptive control is found to efficiently target the resonant tone with little disturbance to the mean features. The framework is not sensitive to sensor placements, enabling actuator design under physically realizable spatial locations in practical implementation. To reflect physical limitations, constraints are imposed on the controller model. It is found that the restricted controller yields greater vortex suppression due to repeated transitory stabilization of the shear layer instability. Statistical analysis reveals intermittent low-pressure events are responsible for the characteristic frequency, which are largely suppressed by adaptive feedback control.