Prediction of the flow response of a turbulent flame to acoustic pertubations based on mean flow resolvent analysis

Resolvent analysis is applied to a non-reacting and a reacting swirled jet flow. Time-averaged flows as input for the resolvent analysis and validation for the results of the resolvent analysis are obtained by experiments. We show that in the non-reacting (cold) flow case, the resolvent analysis is capable of predicting the hydrodynamic response to upstream harmonic acoustic forcing if the flow shows low-rank behavior. This is the case for low and moderate acoustic forcing amplitudes. Even for very strong acoustic velocity amplitudes, that are of the same order of magnitude as the flow velocity, the resolvent analysis still provides reasonable results. The method also yields very good results for the reacting flow in terms of velocity fluctuation and heat release response to the acoustic forcing. This confirms the idea that the resolvent method could be applied to estimate the Flame Transfer Function based on the mean flow and flame.