Parallel Preconditioned Iterative Solvers for Real and Complex Block-Structured CFD Problems

Abstract

At the Institute for Propulsion Technology of the German Aerospace Center (DLR), the parallel simulation system TRACE (Turbo-machinery Research Aerodynamic Computational Environment) has been developed specifically for the calculation of internal turbo-machinery flows. The finite volume approach with block-structured grids requires the parallel, iterative solution of large, sparse real and complex systems of linear equations. For convergence acceleration of the iteration, adequate parallel preconditioners for real and complex matrix problems have been investigated. Special focus was put on the possibility of a matrix-free implementation of the preconditioned solvers. Numerical and performance results of these methods will be presented for typical TRACE problems on multi-core architectures together with an analysis of the pros and cons of the complex problem formulation, e.g. regarding the ratio of calculation operations to memory accesses.