Exploration of Acoustically Coupled Combustion Instabilities via Simulations and Experiments

These computational and experimental studies explore the combustion dynamics of laminar jet diffusion flames in the presence of a standing acoustic wave, conducted in the vicinity of both a pressure node (PN) and antinode (PAN). In the numerical simulations, the CELESTE code, a compressible, implicitly filtered LES solver, is used with the Westbrook–Dryer finite-rate chemistry model [Westbrook & Dryer, CST 2007] to represent the methane-air reaction. Single jet flames are studied in a three-dimensional domain representing the experimental waveguide used in single fuel jet studies with a small offset from a pressure node [Sim, et al., CST 2020; Vargas, et al., JFM 2023]. Comparisons are made with experimental observations of flame response and dynamics quantified via proper orthogonal decomposition (POD) of high speed visible imaging for PN excitation at various amplitudes and at a forcing frequency of 332 Hz. Additional recent experimental studies, involving excitation of various jet flames in the vicinity of a PAN at different frequencies and involving both single and coaxial jets, are also described here, with the potential for comparison with future simulations.