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The effect of number of mesh elements on the result was also carry out. Coarse mesh, medium mesh and fine mesh were created and the result pressure drop across the turn from each mesh were was compared. This analysis will provide confidence on the accuracy of certain mesh. If the changes in mesh elements does not result in a lot of change in result,pressure coefficient drop, it is concluded that the mesh elements is refine enough that the truncation error can be neglected. Following table shows the summary of 3 meshes created for mesh sensitivity analysis. Please refer back to figure 2 for corresponding design parameters
Mesh | Number of Mesh Elements | Wall Boundary Layer Conditions | Second Mesh Edge | Third Mesh Edge | Fourth Mesh Edge |
|---|---|---|---|---|---|
Coarse | 18762 | First row = 0.003 | Interval size = 0.005 | Interval size = 0.002No grading | Interval size = 0.002No grading |
Medium | 30000 | First row = 0.003 | Interval size = 0.005 | Interval size = 0.002 | Interval size = 0.002 |
Fine | 52260 | First row = 0.003 | Interval size = 0.005 | Interval size = 0.002No grading | Interval size = 0.002No grading |
2.6 Parameterization
At the later stage of project, after the good solution was obtained, the effect of geometry on results was analyzed. Different clearance height was used for analyzing new results as a result of this effect. It would be tedious to individually recreate each geometry and mesh for different clearance height from scratch. For this reason, parameterization technique was used. The original Gambit journal file was modified to include the variable clearance height. Using this method, changes in corresponding clearance height was plug into the journal file and run using Gambit to obtain desired mesh and geometry. The journal files used for such parameterization is included in the Appendix.
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