Iterative Substructering Schemes for Fluid Structure Interaction

This paper discusses partitioned analysis approaches for the transient interaction of incompressible viscous flows and nonlinear flexible structures with large deformations. It is shown that for this kind of coupled systems the commonly used sequential staggered coupling schemes exhibit weak instabilities and may eventually fail, mainly due to inconsistencies in the coupling boundary conditions. As best remedy to this problem subiterations should be invoked which ensure kinematic and dynamic continuity across the fluid-structure interface, thus ensuring stable and accurate numerical solutions even for long-time simulations. For the desirable acceleration of convergence of such iterative substructuring schemes two robust and problem-independent methods are proposed and their efficiency is demonstrated with selected numerical examples.