Deutsche Jahrestagung fur Akustik (DAGA2010) edition:36 location:Berlin, Germany date:15-18 March 2010
Hybrid CAA methodologies, based on domain decomposition, are commonly considered as the most appropriate technique for the numerical simulation of aerodynamically generated noise and their far-field propagation with a reasonable computational effort. A crucial step, largely determining the accuracy of the final acoustic results, is the coupling between the aerodynamic source region and the acoustic propagation region. It is known that the spatial and temporal truncation of the source domain simulation together with the interpolation from the ‘fine’ source domain mesh to the ‘coarse’ acoustic grid strongly influence the aeroacoustic radiation. When using a compressible flow simulation, the acoustic fluctuations, which are inherently present in the source domain results, can introduce an additional source of errors in the aeroacoustic radiation predictions. In this case, an aerodynamic/acoustic splitting technique, which allows separating the aerodynamic and acoustic fluctuations from the source domain simulation, can largely improve the accuracy of the aeroacoustic prediction. This paper illustrates the benefits of using this aerodynamic/acoustic splitting technique for a number of commonly used CAA benchmark problems. It is shown that the final accuracy of hybrid CAA methodologies can be largely improved, with only a minimum of additional computational effort, by extracting accurate coupling information from the source domain results.