Comparison of a Structured-LES and an Unstructured-DES Code for Predicting Combustion Instabilities in a Longitudinal Mode Rocket

Both LES and DES area capable of simulating self-excited combustion instability. Agreement between the simulations and experiments for the unstable case was good. The marginally stable case proved more difficult Cyclic Heat release was captured. LES had a delayed reignition, likely responsible for the higher amplitudes. Cyclic Heat release was captured along with reignition event. Some differences in predictions are due to differences in the grids. No apparent winner, both approaches have strengths and weaknesses. The original document contains color images. Contains briefing charts only.