A new domain decomposition method using virtual sub-domains

Abstract

This chapter describes a new Domain Decomposition Method for unstructured grids by using Virtual Sub-domains and a genetic algorithm. The domain decomposition technique is one of key issues in parallel computation, especially, when unstructured grid systems are employed, it influences the efficiency of parallel processing. Furthermore, this new method has a capability to perform partitioning grid in parallel processing. The new method was applied to the flow around a cylinder to examine its performance under a workstation cluster. The unstructured grid system has been widely used in computational fluid dynamics (CFD), because of its advantages over the structured grid to treat complicated geometries and to automatically generate grids. In parallel CFD, domain decomposition is mostly employed to distribute the work load of computation to each processor. The chapter discusses several standard domain decomposition methods, such as the graph bisection method, the coordinate bisection method, and the spectral bisection method. It concludes that the new method did not show so good a performance as expected for sample problems described in the chapter. However, it is expected that it would show a better result for a larger gird system.