Accuracy of numerical solutions of turbulent flows requires some consideration during the mesh generation, as solutions are significantly affected by the presence of walls. Due to the strong interaction between the mean flow and turbulence effects, the numerical results for turbulent flows tend to be more grid-dependent than those for laminar flows. It is therefore recommended to resolve the flow field with sufficiently fine meshes in the regions where the mean flow changes rapidly and where shear layers have large strain rates, such as near walls (Fluent Inc.,2003). The near-wall grid resolution was applied on the wall unit,y+, which is defined as: