Computation of turbulent premixed flames response to inlet velocity oscillations

Combustion instability generally refers to a process where the pressure or velocity fluctuations couple with the unsteady heat release rate in a positive manner leading to growth of the pressure fluctuation which can end up damaging the combustion system. The relation between the velocity perturbation and the heat release rate is typically described by a “Flame Transfer Function” (FTF) H(A, f), with forcing amplitude A and frequency f . It is defined as