CALCULATION OF FLUID-FLOWS WITH STAGGERED AND NONSTAGGERED CURVILINEAR NONORTHOGONAL GRIDS - A COMPARISON

This article compares two finite-volume methods for calculating flows inside complex geometries by curvilinear nonorthogonal coordinates. One method is based on a staggered grid arrangement together with physical covariant velocity projections as dependent variables in the momentum equations, and the other method is based on a nonstaggered grid arrangement together with Cartesian velocity components. Both methods use the SIMPLE algorithm. The comparison indicates that the two methods produce results with similar accuracy after about the same number of iterations. The nonstaggered method seems to manage highly distorted grids better than the staggered method, while the staggered method reaches a grid-independent solution earliest for flow with high pressure gradients. However, due to the simpler nonstaggered grid arrangement, reduced computer program system and reduced memory and calculation time, this method is recommended when using curvilinear nonorthogonal coordinates.