Coarse-grid treatment in parallel AMG for coupled systems in CFD applications

We present an agglomeration approach for the solution of the coarse-grid problems in algebraic multigrid for coupled systems. Our implementation relies on an appropriate reordering of the variables of the merged systems. A benchmark from fluid dynamics, representing the important class of mixed elliptic–hyperbolic problems, is used to demonstrate that the performance of the suggested agglomeration scheme comes much closer to the desired behaviour of the ideal multigrid than that of alternatives described in the literature.

► Implementation of agglomeration scheme for coupled systems.
► Benchmarks on different coarse-grid treatment techniques.
► Efficient method for coupled systems in fluid dynamics.