EFFICIENT PARALLELIZATION OF A PARABOLIZED FLOW SOLVER

This article describes application of our theory of parallelization of implicit ADI schemes to parabolized flows. A parallel multi-domain ve rsion of a turbulent developing flow in a straight duct (case A) and v iscous flow in a curved duct (case B) are presented. Semi-implicit and explicit methods for the determination of boundary values for the aux iliary ADI functions on the interfaces between the sub-domains are uti lized. Numerical runs show that the proposed algorithm is valid in the regions with rapidly varying fields of governing variables (near-entr ance region for the case A, region 30 degrees < theta < 60 degrees for the case B) as well as in the regions with slow axial modification of the flowfield. The algorithm is suitable for small transverse velocit y (case A) and for transverse velocity of order of streamwise velocity (case B). A simplified version of our theoretical model of parallel e fficiency is developed and utilized for optimal multidomain partitioni ng. Computer runs of the multi-domain code are done on a Meiko CS and on a DEC Alpha farm with PVM communication software. The predictions o f parallel efficiency obtained by the model compare well with those of actual computer runs. The parallelization parameters obtained are qui te different for two considered MIMD machines. This fact confirms the importance of a priori estimation of parallelization efficiency of an algorithm and correct choice of a parallel computer. (C) 1998 Elsevier Science Ltd. All rights reserved.