Abstract : The objective of this research was to improve understanding of the mechanisms by which flow, mixing and combustion processes are coupled to acoustic fields in liquid propellant rocket motors. Particular attention was focused on analyses of amplification mechanisms coupled with finite rate chemical reactions by use of numerical and analytical methods. A theoretical explanation of empirical correlation of instability boundaries for engine test results for LOX/RP-1 rockets was developed on the basis of amplification by finite rate chemical reactions in strained mixing layers. In addition, a new numerical computation of nonlinear amplification mechanisms in LOX/GH2 combustion suggested a possible explanation of threshold phenomena found in liquid propellant rockets.