Computational fluid dynamics methodology to predict the effects of combusting flows on acoustic pressure oscillations in liquid rocket engines (LREs) is under development. 'Me intent of the investigation is to develop the causal physics of combustion driven acoustic resonances in LREs. The crux of the analysis is the accurate simulation of pressure/density/sound speed in a combustor which when used by the FDNS-RFV CFD code will produce realistic flow phenomena. An analysis of a gas generator considered for the Fastrac engine will be used as a test validation case.Farmer, Richard C. and Cheng, Gary C.Marshall Space Flight CenterLIQUID PROPELLANT ROCKET ENGINES; PERFORMANCE TESTS; COMBUSTIBLE FLOW; PRESSURE OSCILLATIONS; SIMULATION; SOUND PRESSURE; COMPUTATIONAL FLUID DYNAMICS; COMBUSTION; COMBUSTION CHAMBERS; GAS GENERATORS...