High Performance Computing on Vector Systems-P6: In March 2005 about 40 scientists from Europe, Japan and the US came together the second time to discuss ways to achieve sustained performance on supercomputers in the range of Teraflops. The workshop held at the High Performance Computing Center Stuttgart (HLRS) was the second of this kind. The first one had been held in May 2004. | A Hybrid LES CAA Method for Aeroacoustic Applications 147 The zonal approach results in a pronounced improvement of the local accuracy of the solution. The skin-friction coefficient distribution and the near wall as well as the wake velocity profiles show a convincing agreement with the experimental data. The experience with the present global LES method evidences that good results can be achieved if the resolution requirements are met 5 . For this reason the next step will be to concentrate on the improvement of the computational setup. Since the outer part of the flow field over an airfoil is predominantly two-dimensional and laminar only a quasi-2d calculation will be performed in this area in the next step. For this purpose a 2D 3D coupling technique has been developed for the structured solver. With this technique it is possible to increase the near wall resolution while keeping the overall computational cost at a relatively low level. Next hybrid RANS LES coupling techniques are contemplated for the improvement of the overall numerical method. Furthermore with respect to the simulation of the sound field the LES data from the zonal approach will be postprocessed to determine the source terms of the acoustic perturbation equations which were already successfully used in 1 . 6 CAA for Combustion Noise This research project is part of the Research Unit FOR 486 Combustion Noise which is supported by the German Research Council DFG . The objective of the Institute of Aerodynamics of the RWTH Aachen University is to investigate the origin of combustion noise and its mechanisms. The LES for the two-step approach is performed by the Institute for Energy and Powerplant Technology from Darmstadt University of Technology followed by the CAA simulation to compute the acoustical field. This hybrid LES CAA approach is similar to that in 1 . However in this study the Acoustic Perturbation Equations are extended to reacting flows. In flows where chemical reactions have to be
