TURBULENT-FLOW CALCULATIONS BY THE NONLINEAR MULTIGRID METHOD

The nonlinear Multi-Grid Method (NMGM, HACKBUSCH [2], [3]) is a relati vely unexplored alternative to the Full Approximation Storage method ( FAS, BRANDT [1]). Excellent convergence of the NMGM was reported in [3 ] for a non-linear Poisson problem in a square. In the present paper, the NMGM is applied to a steady-state three-dimensional turbulent flow problem. The problem arose from the study of a row of jets supplying the air into the chamber of an industrial furnace. The description of the NMGM is given in [2]. Here, we present the flow problem in its ana lytical and discrete form, describe our choices for the various elemen ts of the NMGM, and demonstrate a very good performance of the method in a series of convergence tests. The locally coupled method (VANKA [1 3], ROLLET et al. [11]) is used for smoothing the residuals of the con tinuity and momentum equations. The best performance is obtained when a simplified form of the pressure correction method (PATANKAR and SPAL DING [9]) is additionally applied to enforce the given mass flows thro ugh the flowfield sections.