Vortex-sound Generated Pressure Oscillations Simulation in Internal Flow by means of Q-1D Model

The quasi-steady operative condition of large solid rocket motors could exhibit the presence of sustained pressure and thrust oscillations, at a frequency close to the acoustical fundamental, or one of its multiple, of their motor chamber. The phenomenon occurs because of a coupling between shear layer instabilities, with vorticity generation and convection, and acoustical feedback resulting from destroy of vorticity by some geometrical features of combustion chamber, as port area variations or nozzle walls. In the present work the analysis of solid propellant rocket motor aero-acoustic phenomena is obtained by applying a quasi-onedimensional model. The proposed model is derived formally from the Euler conservation laws. The model, implemented into a code named AGAR (Aerodinamically Generated Acoustic Resonance), is applied to a cold flow in a axisymmetric combustor as test case.