Self-organizing hybrid Cartesian grid/solution system with multigrid

An automatic adaptive hybrid Cartesian grid generation and solution system is presented together with applications for turbulent flows around complicated three-dimensional geometries. The primary computational grid is an octree Cartesian grid with a cut-cell approach. A quasi-prismatic grid may be added for resolving the boundary layer region of viscous flow around the solid body. For external flow simulations the flow solver TAU from the Deutsches Zentrum fiir Luftund Raumfahrt is integrated in the simulation system. Coarse grids are generated automatically, which are required for multilevel smoothing. The initial hybrid Cartesian grid is improved with help of several adaptation features, which are optimized in order to avoid any user interaction. Therefore, the final grid depends only on the particular geometry and flow structure (selforganized grid).