Department of Aerospace Engineering, University of Glasgow
Abstract
Increasingly large scale computations are using unstructured discrete computational grids.
A typical example is unstructured grid calculations based on finite volume methods
(FVM) in computational fluid dynamics (CFD). One of the efficient ways to deal with
such large scale problems is parallelization. The present paper will focus on domain/mesh
decomposition. This is the first step for distributing unstructured computational domains
on a MIMD-type parallel computer system. A graph theory framework for this problem
will be constructed. Based on the framework three domain decomposition algorithms:
recursive coordinate bisection (RCB), recursive angular bisection (RAB) and recursive
graph bisection (RGB), will be introduced, tested and discussed. A pre-ordering and
smoothing technique is proposed. It is necessary in the procedure for obtaining a 'good'
domain partitioning result. Another interesting method, called the domain decomposition
technique (DDT), is also investigated, which is driven in an inverse way, i.e. domain
decomposition followed by mesh construction. Finally a simple and direct strategy called
the mesh tailor technique (MTT) is discussed. Numerical comparisons using 2D CFD
problems will be given. The further research work required to carry out a parallel
implementation of a flow problem will be mentioned