NONUNIFORM GRID ACCURACY TEST APPLIED TO THE NATURAL-CONVECTION FLOW WITHIN A POROUS-MEDIUM CAVITY

The accuracy of numerical results obtained by using nonuniform grid di stributions is strongly affected by the size of the grid spacing. The present work focuses on a detailed procedure for the accuracy tests of the numerical results obtained by using nonuniform grid distributions . It is shown that the degree of nonuniformity of a certain grid distr ibution with a fixed number of grid lines also has a strong effect on the numerical results. For a fixed number of grid lines there is only one optimum nonuniform grid distribution for each physical case. Furth ermore, an accurate nonuniform grid for a physical situation with stee p gradients presents a very low efficiency in terms of CPU time when u sed for simulating cases with smaller gradients.