ON THE COMPUTATIONAL-EFFICIENCY AND IMPLEMENTATION OF BLOCK-ITERATIVEALGORITHMS FOR NONLINEAR COUPLED PROBLEMS

Outlines a general methodology for the solution oi the system of algeb raic equations arising from the discretization of the field equations governing coupled problems. Considers that this discrete problem is ob tained from the finite element discretization in space and the finite difference discretization in time. Aims to preserve software modularit y, to be able to use existing single field codes to solve more complex problems, and to exploit computer resources optimally, emulating para llel processing. To this end, deals with two well-known coupled proble ms of computational mechanics - the fluid-structure interaction proble m and thermally-driven flows oi incompressible fluids. Demonstrates th e possibility oi coupling the block-iterative loop with the nonlineari ty of the problems through numerical experiments which suggest that ev en a mild nonlinearity drives the convergence rate of the complete ite rative scheme, at least for the two problems considered here. Discusse s the implementation of this alternative to the direct coupled solutio n, stating advantages and disadvantages. Explains also the need for on line synchronized communication between the different codes used as is the description oi the master code which will control the overall alg orithm.