Adaptive Local Refinements

The applications under consideration in this book are extremely challenging with respect to computing time and memory. The parallelization of the flow solvers and the use of multigrid solvers have enabled the computation of viscous (steady-state) flows around full aircraft within a few hours. For future even more complex applications, however, the computing times have to be reduced further. A very promising approach is to use adaptive grids. In this section we describe the idea of this approach and show that it can be combined with multigrid in a natural and straightforward way. The problem of defining appropriate refinement criteria and the problems of the parallelization of block-structured multigrid are discussed briefly.