2-GRID FINITE-ELEMENT FORMULATIONS OF THE INCOMPRESSIBLE NAVIER-STOKES-EQUATIONS

The paper compares two different two-grid finite element formulations applied to the Navier-Stokes equations, namely a multigrid and a mixed or composite formulation. In the latter case the pressure is interpol ated on a coarser grid than the velocity; using mixed elements instead of mixed interpolation functions. In the multigrid formulation an equ al-order interpolation is used on the same elements. A pressure Poisso n formulation is used in both cases. Computational results are present ed to compare the methods and comparisons are also made with other res ults. (C) 1997 John Wiley & Sons, Ltd.