Parallel ILU Preconditioning, A Priori Pivoting and Segregation of Variables for Iterative Solution of the Mixed Finite Element Formulation of the Navier - Stokes Equations
 

Sven Øivind Wille
Oslo University College


Resumo: A parallel ILU preconditioning algorithm for the Navier - Sokes equations have been developed. The computational mesh is divided into N subdomains which are processed in parallel in different processors.During ILU factorization, matrices and vectors associated with the nodes on the interface between the subdomains are communicated to the equation matrices to the adjacent subdomain. The bases for the parallel algorithm are an appropriante node ordering scheme and a segregation of  velocity and pressure degrees of freedom. The inner nodes of the subdomain is numbered first and then the nodes on the interface between the subdomains. To avoid division by zero during the ILU factorization the equations corresponding to the velocity degrees of freedom are assembled first in the global equation matrix, and at last the equations corresponding to the pressure degrees of freedom.