On the Simulation of Noise Emissions by Turbulent Non-Premixed Flames
This work introduces an efficient LES/CAA hybrid approach to simulate the noise emissions by turbulent non-premixed flames. The reactive flow field and the combustion noise sources are solved for by means of a large eddy simulation (LES) utilizing a low Mach number approximation. The acoustic pressure field in the vicinity of the flame is then described with a wave propagation method, solving the wave equation directly. This computational aeroacoustics (CAA) methodology accounts for inhomogeneous fluid properties, as they are present in a turbulent flame. Both originally independent solvers are combined into a single tool allowing for an efficient implementation and parallelization strategy. The presented LES/CAA approach has been applied to different turbulent non-premixed flames, the LES has been validated, and the resulting noise emissions have been compared successfully to experimental measurements. Possible future extensions accounting for acoustic feedback onto the flame are discussed.