An ILU Smoother for the Incompressible Navier-Stokes
Equations in General Coordinates

S. Zeng and P. Wesseling
Department of Technical Mathematics and Informatics
Delft University of Technology
Mekelweg 4
2628 CD Delft
The Netherlands


ILU smoothers are good smoothers for linear multigrid methods. In this paper, a new ILU smoother for the incompressible Navier-Stokes equations CILU (Collective ILU), is designed, based on r-transformations. Existing ILU decompositions factorize the matrix with real elements. In CILU the elements of the matrix that is factorized are submatrices, corresponding to the set of physical variable. A multigrid algorithm using CILU as smoother is investigated. Average reduction factors and limiting reduction factors are measured to explore the performance of the algorithm. The results show that CILU is a good smoother.

Contributed Februrary 4, 1994.