Abstract
The spectral characteristics of combustion noise is dictated by the temporal correlation of the heat release rate fluctuation. This paper investigates the two-point space-time correlation of heat release rate fluctuations by analysing recent direct numerical simulation (DNS) data of turbulent premixed flames. The results show that this correlation decays rapidly in both space and time due to the abrupt fluctuation of the heat release rate. The two-point space-time correlation can be modelled by Gaussian-type functions including the streamwise direction with strong convection. A flat low-frequency dependence is observed for the spectrum of the correlation function, which will allow the modelling of the spectral peak and the low-frequency spectral slope of combustion noise when multiplying the term omega^2 (omega is the angular frequency). This exploratory work shows the potential of this correlation function for capturing the spectral shape of combustion noise.