Numerical simulations are becoming more and more important for the prediction of noise generation and propagation. Particularly for sound propagation, classical CFD methods are too expensive whereas optimized CAA methods are well-established. Applying a finite-difference CAA method employing high order discretization schemes for more complex geometries necessitates block-structured curvilinear body-fitted grids. This causes two major difficulties; on the one hand it is tedious and challenging to generate a high quality mesh with minimally distorted cells, and on the other hand the large exchange areas at the block boundaries resulting from the high order scheme cause grid singularities at the intersections of odd numbers of block interfaces, which degrade the quality of the simulation results. To avoid such problems, speed up the grid generation process and to increase the overall grid quality an overset grid method, also known as the Chimera technique was implemented. A nearly orthogonal and equidistant background grid is utilized in combination with separately-meshed, high quality, body-fitted overset grids for the solids in the domain. The data transfer between the individual overset grids and the background grid is accomplished by an interpolation method.
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