| This project focused on the development of a computationally-light form of AMG, Aggregation-type Algebraic Multigrid (AggMG). The AggMG developed uses a top-down approach, where the original problem is coarsened by recursive partitioning of the problem mesh.; A new solver library, FlexMG, was developed to support the AggMG implementation. This framework can also use Geometric Multigrid (GMG), being written concurrently at the Universite Libre de Bruxelles. The multigrid correction can then be used as a pre-conditioner for powerful Krylov subspace solvers, such as the generalized minimal residual (GMRES) algorithm. Accuracy of the AggMG solver was first verified in the turbulent flow solver, SFELES, and solver performance of FlexMG compared to that of published data.; Using FlexMG, large direct numerical simulations (DNS) of two-phase turbulent flow were performed that were previously impossible at the von Karman Institute for Fluid Dynamics (VKI). FlexMG was also integrated with COOLFluid, a modular VKI CFD multi-method code, to show the applicability of the solver to complex 3D geometries.; This project is the first step in the development of a powerful in-house linear iterative solver, and provides the framework for continued study and improvement of multigrid solvers for CFD applications. (Abstract shortened by UMI.)... |
