Dynamic Computational Subgrid Modeling I

In this paper we propose and study a subgrid model for linear convection-diiusion-reaction problems with fractal rough coeecients. The subgrid model is based on extrapolation of a modeling residual from coarser scales using a computed solution on a nest scale as reference. We show in experiments that a solution with subgrid model on a scale h in most cases corresponds to a solution without subgrid model on a scale less than h=4. Acknowledgement The rst author would like to thank Professor Endre S uli for allowing him the opportunity to visit the Oxford University Computing Laboratory during Hilary term 1999, where part of this work took place.