A multipole direct and indirect BEM for 2D cavity flow at low Reynolds number

A multipolar methodology is applied to the boundary element method (direct and indirect formulation) in order to solve bidimentional Stokes cavity flow. The algorithm based on mixed multipolar expansion and numerical integration is applied not only for very large problems but also for intermediate and small problems. In comparison with the direct formulation, the indirect formulation is more stable with the iterative solvers, and does not need to be preconditioned to obtain a fast convergence. A good result in memory saving and computing time is obtained that enables us to run huge examples which are prohibitive for traditional BEM implementations. (C) 1997 Elsevier Science Ltd.