MASSIVELY-PARALLEL FINITE-ELEMENT COMPUTATION OF INCOMPRESSIBLE FLOWSINVOLVING FLUID-BODY INTERACTIONS

We describe our massively parallel finite element computations of unst eady incompressible flows involving fluid-body interactions. These com putations are based on the Deforming-Spatial-Domain/Stabilized-Space-T ime (DSD/SST) finite element formulation. Unsteady flows past a statio nary NACA 0012 airfoil are computed for Reynolds numbers 1000, 5000 an d 100000. Significantly different flow patterns are observed for these three cases. The method is then applied to computation of the dynamic s of an airfoil falling in a viscous fluid under the influence of grav ity. It is observed that the location of the center of gravity of the airfoil plays an important role in determining its pitch stability. Co mputations are reported also for simulation of the dynamics of a two-d imensional 'projectile' that has a certain initial velocity. Specially designed mesh moving schemes are employed to eliminate the need for r emeshing. All these computations were carried out on the Thinking Mach ines CM-200 and CM-5 supercomputers, with major speed-ups compared to traditional supercomputers. The implicit equation systems arising from the finite element discretizations of these large-scale problems are solved iteratively by using the GMRES update technique with diagonal p reconditioners. The finite element formulations and their parallel imp lementations assume unstructured meshes.