Turbulence-Driven Blowout Instabilities of Premixed Bluff-Body Flames

Bluff-body flame instabilities are experimentally investigated under varying turbulence conditions during lean blowout. For all conditions, the blowout process is induced through a temporal reduction of fuel flow rate to capture flame-flow dynamics approaching Simultaneous high-speed particle image velocimetry (PIV), stereoscopic PIV, and C2*/CH* chemiluminescence imaging employed, along with an independent CH* system, instabilities. Proper orthogonal decomposition (POD) dynamic mode (DMD) techniques used identify prominent oscillations evaluate recurring spatiotemporal modes The results reveal that dominant wrinkling characteristics directly dependent on in combustor. Specifically, strongly coupled integral length scales, which were able collapse oscillation frequencies unified value. turbulence-driven shown largely impact magnitude, evolution, oscillatory behavior strain rate. As intensity increased, increases frequency, making it more likely for localized extinctions occur. Additionally, magnitude at high intensities accelerates process.