A Project Summary

This KDI/NCC proposal builds upon a prior NSF HPCC Grand Challenge award (ESC-95-27123) for the highperformance computation of the motion of solid particles in Newtonian and viscoelastic liquids; it aims to use these computations to elucidate fundamental dynamics and solve problems of engineering interest. The Grand Challenge goal was to develop software packages, called particle movers, capable of carrying out direct numerical simulations (“DNS”) of the motion of thousands of particles in 2-D and hundreds in 3-D, in parallel implementation. Two state-of-the-art particle movers were developed. One of these (ALE particle mover) uses a moving unstructured, body-fitted grid, and has given rise to the first and only package which can presently move particles in viscoelastic fluids. The other (DLM particle mover) uses a fixed, regular grid, and represents the particles by a field of Lagrange multipliers which enforce the constraint of rigid-body motion. The DLM particle mover is inventive, and it appears to have great potential with respect to parallel implementation of large numbers of particles in realistic flow conditions. Both methods use a new combined weak formulation in which the fluid and particle equations of motion are combined into a single weak equation of motion from which the hydrodynamic forces and torques on the particles have been eliminated. These and other results achieved in the Grand Challenge project have opened new and promising lines for investigation. See the project Web site,