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Figure 10. Wall Yplus
Figure 10 shows that the yplus at wall was values were consistently less than 5. According to FLUENT documentations mentioned that documentation "the mesh should be made either coarse or fine enough to prevent the wall-adjacent cells from being placed in the buffer layer (yplus = 5~30)". Since the yplus from the model was consistenly consistently less than zero and was in the region of five (inside the viscous sublayer, ) the turbulence flow near the wall walls was able to be resolved properly.
Figure 11. Mesh Sensitivity Analysis
Figure 11 shows the pressure coefficient drop over one turn with for different mesh densities. The pressure drop given by the fine mesh is the most accurate. This is because as the mesh get finer, the truncation error is reduced and In general finer meshes provide more accurate resultresults. However, as the mesh get finer, the computational times also increase. To determine is it worth extra time to obtain further accuracy, mesh sensitivity analysis is carried out. Pressure coefficient drop for three meshes is about the same. Hence it is concluded that coarse mesh is good enough to provide reasonable resultwas refined the pressure drop remained constant as can be seen in figure 11. Hence, it was concluded that results were not sensitive to mesh density and the coarse mesh was sufficient.
Figure 12. Reynolds Number Effect on Pressure Coefficient Drop
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