Modal decomposition of the unsteady non-reactive flow field in a swirl-stabilized combustor operated by a Lean Premixed injection system

This work is focused on the numerical study of low-order coherent structures a high-swirled laboratory-scaled combustor operated by Lean Premixed (LP) injection system in non-reacting conditions through different flow modal decomposition techniques. will provide valuable insight into time-spatial structure detecting spatial patterns. Experiments suggest appearance self-excited hydrodynamic instability characterized single dominant frequency. On one hand, pulsating energy components associated with Precessing Vortex Core (PVC) are identified application Proper Orthogonal Decomposition (POD) to instantaneous velocity field. other Dynamic Mode (DMD) proven effectively highlight relation between frequency most unsteady vortex and their distribution within combustor. Since DMD analysis generates global spectrum which each mode corresponds specific discrete frequency, its has been demonstrated be more efficient than POD when dealing temporally problems. In this way, technique proved robust systematic method that can give accurate consistent interpretations periodic physics underlying instabilities studied present investigation.