EFFICIENT SOLUTIONS SCHEMES FOR INTERFACE PROBLEMS

A computationally efficient two-level iterative scheme is proposed for the solution of the interface problems with Lagrange multipliers, whe re the oscillatory part of the solution is resolved by means of smooth ing using a new, efficient preconditioner whereas the smooth component of the solution is captured by the collocation-based problem on the a uxiliary grid, that is solved directly using a sparse direct solver. A simple adaptive feature is built into the proposed solution method in order to guarantee convergence for ill-conditioned problems. Numerica l results presented for example problems including that of a Boeing cr own panel show that the proposed two-level solution technique outperfo rms the standard, single level iterative and direct solvers.