Stability of a coupling technique for partitioned solvers in FSI applications

This paper focuses on the stability of the coupling iterations in the partitioned approach to fluid–structure interaction. Previous research has shown that the number of coupling iterations increases when the time step decreases or when the structure becomes more flexible which is explained here by Fourier error analysis of the unsteady, incompressible flow in an elastic tube. Substituting a linearized model of the structural solver into the flow solver makes the coupling more stable but is impracticable if the flow solver is a black box. Therefore the coupling iterations are stabilized by coupling with reduced-order models and Aitken underrelaxation.