NUMERICAL COMPARISON OF MOMENTUM INTERPOLATION METHODS AND PRESSURE-VELOCITY ALGORITHMS USING NON-STAGGERED GRIDS

Finite-volume calculations of laminar separated flow around a fence are presented using a non-staggered grid system. Using the pressure-weighted interpolation method (PWIM), the role of the under-relaxation factor in this method has been studied. The performance of two pressure-velocity coupling algorithms, viz. SIMPLE and PISO, have been compared as well as the solution fields obtained using non-staggered and staggered grids. A detailed study has been conducted to investigate the occurrence of physically unrealistic convective velocities in the solution fields. The numerical results show that solutions obtained using non-staggered grids are as accurate as those obtained using staggered grids. The presence of very small under/overshoots in the estimated convective fluxes is related to the simultaneous presence of high peclet numbers and rapidly varying pressure gradients. However, for the complex separated flow investigated, no induced errors were detected in the solution field.