Numerical comparison between the Dynamic Mode Decomposition and the Arnoldi extraction technique on an afterburner test case

The fairly recent methodology, the so called Dynamic Mode Decomposition, is investigated for the Afterburner test case in order to see if the methodology is able to capture thermo-acoustic instabilities. Previous papers deal with the prediction of such instabilities using the Arnoldi extraction technique. The present paper compares these two approaches in order to see their advantages and drawbacks regarding the present case of study. The linearized solver chosen in the Arnoldi extraction technique is based on the Linearized Navier Stokes Equations (LNSE). As a main concern of the study, the structures and frequencies of the buzz (~ 120 Hz) and the screech modes (~ 1200 Hz) are compared using both methodologies. Additional cases are also studied acoustic liner walls in computational domain and tuned to damp the Screech mode. In these cased the methodologies are tested for their ability to predict the damping effect of the liner. \ua9 2012 by Guillaume Jourdain Lars-Erik Eriksson. Published by the American Institute of Aeronautics and Astronautics, Inc