Solid Rocket Combustion Phenomena

This Final Technical Report describes completed research accomplishments and ongoing activities that are focused on the evolution of boundary driven acoustic disturbances in a low Mach number shear flow like that found in the chamber of a solid rocket engine. The completed work (manuscripts in Appendices A and B) focuses on the relatively complex wave systems that appear in a two-dimensional planar shear flow following the refraction of very simple, initially planar axial disturbances. Work in progress emphasizes; (1) the characteristics of acoustic disturbances driven by sidewall mass addition in semi-confined channels and tubes, (2) the role of strongly injected Stokes boundary layers in providing a transition from the acoustic flow to the no-slip condition on the wall, and (3) mathematical methods required to deal with nonlinear processes within an acoustically disturbed flow. The review of our work emphasizes the importance of studying the evolution of boundary driven acoustic disturbances, primarily to gain an understanding of how small burning rate transients (modelled by unsteady wall injection) lead to large engine chamber responses observed in unstable solid rockets.