Convergence acceleration of segregated algorithms using dynamic tuning additive correction multigrid strategy

A convergence acceleration method based on an additive correction multigrid -SIMPLEC (ACM-S) algorithm with dynamic tuning of the relaxation factors is presented. In the ACM-S method, the coarse grid velocity correction compon ents obtained from the mass conservation (velocity potential) correction eq uation are included into the fine grid momentum equations before the coarse grid momentum correction equations are formed using the additive correctio n methodology. Therefore, the coupling between the momentum and mass conser vation equations is obtained on the coarse grid, while maintaining the segr egated structure of the single grid algorithm. This allows the use of the s ame solver (smoother) on the coarse grid. For turbulent flows with heat tra nsfer, additional scalar equations are solved outside of the momentum-mass conservation equations loop. The convergence of the additional scalar equat ions is accelerated using a dynamic tuning of the relaxation factors. Both a relative error (RE) scheme and a local Reynolds/Peclet (ER/P) relaxation scheme methods are used. These methodologies are tested for laminar isother mal flows and turbulent flows with heat transfer over geometrically complex two- and three-dimensional configurations. Savings up to 57% in CPU time a re obtained for complex geometric domains representative of practical engin eering problems. Copyright (C) 1999 John Wiley & Sons, Ltd.