Efficiency of fluid-structure interaction simulations with adaptive underrelaxation and multigrid acceleration

In the present paper the efficiency of acceleration techniques for fluid-structure interaction computations are investigated. The solution procedure involves the finite volume flow solver FASTEST, the finite-element structural solver FEAP, and the coupling interface MpCCI. Within the employed partitioned solution approach, a geometric multigrid solution strategy on moving grids for the fluid domain is introduced. In particular, the order in which the convective fluxes have to be treated within the pressure-correction smoothing procedure is addressed. For reducing the coupling iteration steps an adaptive underrelaxaation algorithm is employed. Both acceleration techniques are investigated separately and in combination with respect to numerical efficiency. As test configuration a representative three-dimensional ullsteady coupled problem is considered.