PARALLEL FINITE-ELEMENT SIMULATION OF 3D INCOMPRESSIBLE FLOWS - FLUID-STRUCTURE INTERACTIONS

Massively parallel finite element computations of 3D, unsteady incompr essible flows, including those involving fluid-structure interactions, are presented. The computations with time-varying spatial domains are based on the deforming spatial domain/stabilized space-time (DSD/SST) finite element formulation. The capability to solve 3D problems invol ving fluid-structure interactions is demonstrated by investigating the dynamics of a flexible cantilevered pipe conveying fluid. Computation s of flow past a stationary rectangular wing at Reynolds number 1000, 2500 and 10(7) reveal interesting flow patterns. In these computations , at each time step approximately 3 x 10(6) non-linear equations are s olved to update the flow field. Also, preliminary results are presente d for flow past a wing in flapping motion. In this case a specially de signed mesh moving scheme is employed to eliminate the need for remesh ing. All these computations are carried out on the Army High Performan ce Computing Research Center supercomputers CM-200 and CM-5, with majo r speed-ups compared with traditional supercomputers. The coupled equa tion systems arising from the finite element discretizations of these large-scale problems are solved iteratively with diagonal precondition ers. In some cases, to reduce the memory requirements even further, th ese iterations are carried out with a matrix-free strategy. The finite element formulations and their parallel implementations assume unstru ctured meshes.