Linear and nonlinear stability of acoustics with nonuniform entropy in chambers with mean flow
Abstract
The linear and quadratic coupling of small fluctuating quantities of entropy in the acoustic field of a chamber are studied in order to help predict stability in ramjet combustion chambers. In the linear case, the entropy and acoustics are decoupled in the interior of the chamber. All linear coupling occurs at the boundary conditions. For cases where the entropy fluctuations are of the same order of magnitude as the pressure oscillations and the coupling is of order one, the linear stability of the acoustic field is strongly dependent upon the entropy fluctuations. In the nonlinear case, the acousticentropy interactions are much smaller than the acousticacoustic interactions in the limit of the assumptions.
 Publication:

American Institute of Aeronautics and Astronautics Conference
 Pub Date:
 June 1987
 Bibcode:
 1987aiaa.confR....H
 Keywords:

 Acoustic Instability;
 Combustion Stability;
 Entropy;
 Flow Chambers;
 Frequency Stability;
 Coupled Modes;
 Flow Distribution;
 Pressure Oscillations;
 Ramjet Engines;
 Sound Waves;
 Acoustics