Acousticmean flow interaction in solid rocket motors using NavierStokes equations
Abstract
The presented numerical solution of laminar, twodimensional, compressible and unsteady NavierStokes equations is aimed at a complete description of acoustic boundary layers that develop above a burning propellant. Such acoustic boundary layers are responsible for the socalled flow turning losses and also govern the local unsteady flow conditions that are seen by the burning propellant and to which it finally responds. In those respects, a complete understanding of such acoustic boundary layers is essential to improve existing solid rocket stability prediction codes. The full numerical solution of the NavierStokes equations permits to naturally incorporate into the analysis all the features of twodimensional rocket chamber mean flow field. After a standing wave pattern is established through forcing at a given frequency, a special Fourier treatment is used to put the numerical results in a form directly comparable to available linear acoustic data. The presented results indicate that the acoustic boundary layer is substantially thinner than predicted by simplified models. Moreover, its acoustic admittance is found to significantly vary along the chamber, a result that is of major importance to stability predictions. Finally, the acoustic field is found to be rotational over a significant volume of the chamber, leading to a volume flow turning loss, rather than to a pure surface effect as usually assumed.
 Publication:

AIAA, ASME, SAE, and ASEE, 24th Joint Propulsion Conference
 Pub Date:
 July 1988
 Bibcode:
 1988jpbm.confQ....V
 Keywords:

 Acoustic Properties;
 Laminar Flow;
 NavierStokes Equation;
 Solid Propellant Combustion;
 Solid Propellant Rocket Engines;
 Two Dimensional Flow;
 Acoustic Velocity;
 Boundary Layers;
 Nozzle Flow;
 Reynolds Number;
 Unsteady Flow;
 Wave Functions;
 Fluid Mechanics and Heat Transfer