Hybrid DRP-BEM method for acoustics of buoyancy driven plumes

In this paper a hybrid method for aeroacoustics is developed. The numerical method consists of using Large-Eddy-Simulation (LES) for construction of the acoustic source terms, the dispersion-relation-preserving (DRP) scheme of Tam¹ for solving the linearized Euler equations in the near field and the boundary element method (BEM) for far field propagation. Lighthill's formulation of the source term² is used in this study in addition to an energy term that accounts for the direct combustion noise due to heat release rate. The developed method is used to investigate the noise of a 2-D reacting plume. The predicted field shows that the acoustic sources is dominated by the entropy term. It is also noted that reactive plumes generate low frequency noise. In addition a low amplitude high frequency noise was detected due to the direct combustion noise.