Backend. The CFD software

 

The FlowGrid system features a state-of-the art CFD solver as a backend. The CFD software have been designed using OO techniques and written in C++. Object oriented techniques enable the creation of data structures and very efficient interfaces between the components.


The solver uses unstructured meshes with the finite volume collocated approach. The control volumes can have arbitrary number of faces and points. The combined ‘face based’ and ‘volume based’ pointer system provides very efficient way of treating mesh related computations and solving finite volume equations. The solver uses a segregated iteration procedure to solve Navier-Stokes equations. The pressure-velocity coupling is treated using a modified SIMPLE method and extended on the arbitrary unstructured meshes by the Rhie and Chow interpolation. The arbitrary connectivity between control volumes requires appropriate linear equation solvers. A highly efficient library of linear equation solvers has been developed to solve the finite volume equations on the arbitrary unstructured meshes. The library includes ILU (incomplete factorisation) linear solver and variety of conjugate gradient and conjugate residual based accelerators with ILU preconditioning. It should be noted that the structured meshes are handled using simplified and more efficient implementation. The algebraic multigrid solver with ILU smoother is also available for meshes with structured topologies. The use of unstructured meshes significantly simplified the implementation of parallel computations via domain decomposition. The component structure and clean interfaces between components also suits functional decomposition of the software so they can run efficiently on ‘parallel distributed systems’. Such decomposition has been carried out in this Project using a Globus-enabled implementation of MPI.

 
 
 

Copyright 2004 FlowGrid Consortium | Please send questions or comments to Norberto.Fueyo@posta.unizar.es, or to any other FlowGrid partner | Last modified on 02/04/2004