Computational Study of Mixed Hydrodynamic-Acoustic Waves in Gas Turbine Afterburner Flows

Other conference contribution, 2008

A previously developed eigenmode extraction algorithm, based on a time-domain linearized flow solver combined with Arnoldi’s method, has been applied to a generic afterburner test case as a tool for studying combined hydrodynamic-acoustic waves. A porous wall model was included in the linearized flow solver in order to simulate the effects of acoustic liners inside the combustor domain. Results obtained demonstrate that modes consisting of mixed hydrodynamic-acoustic waves are mainly found in the typical lower screech regime, where Strouhal numbers for the flameholders involved are in the range 0.1-0.2. Furthermore the porous wall model applied was found to be able to simulate the expected increased damping of several of these mixed modes.