Mitigating thermoacoustic oscillations in coupled systems using asymmetric open-loop acoustic forcing

Open-loop acoustic forcing has proven effective in mitigating thermoacoustic oscillations, primarily in single oscillators. However, optimal forcing strategies for coupled thermoacoustic systems remain largely unexplored. This work investigates the mitigation of thermoacoustic oscillations in a coupled Rijke tube system using asymmetric open-loop acoustic forcing applied to both inlets. We demonstrate that, for a given total input energy to the forcing unit, an optimal energy distribution ratio between the tubes exists, minimizing the global oscillation amplitude. Furthermore, the influence of the relative phase difference between the forcing signals and the effectiveness of mixed-frequency forcing are examined. Our findings reveal the critical role of energy distribution in open-loop control of coupled thermoacoustic systems and demonstrate the potential of asymmetric forcing for enhanced mitigation performance and reduced energy consumption.