Critical region in the spatiotemporal dynamics of a turbulent thermoacoustic system and smart passive control

We develop a passive control strategy for suppressing thermoacoustic instability in bluff-body stabilized premixed turbulent combustor. When the equivalence ratio is varied, there transition from combustion noise to via intermittency perform simultaneous acoustic pressure, 2D-PIV, and CH* chemiluminescence measurements capture pressure fluctuations, velocity field, heat release rate (HRR) field during transition. measure spatial distribution of amplitude at frequency, time-averaged vorticity, HRR, Rayleigh index identify various regions significance. implement by targeting these with steady injection secondary micro-jet air optimize location determine critical region. Targeting region leads greater than 20 dB suppression dominant mode. observe that coherent structure forming shear layer following dump plane gets suppressed, leading an incoherent HRR fluctuations. find correctly identifies optimized instability. In contrast, most significant driving; however, it does not sensitive control. Finally, we extend our analysis determining Hurst exponent measured field. show intermittency, unlike other physical measures. Thus, smart method combining need finding combustor predictive capabilities exponent.