Adjust the boundary layers by setting the edge parameters.

Blocking > Pre-Mesh Params   > Edge Params  

1. Select one of the radial edges as shown in Figure 131: Radial Edge Selected.

   Figure 131: Radial Edge Selected

   
   
   

2. Enter 16 for Nodes.

3. Enter 0.05 for Spacing1.

4. Enable Copy Parameters and ensure that To All Parallel Edges is selected in the Method drop-down list.

5. Click Apply.

   You have adjusted the boundary layers for all edges.

6. Recompute the pre-mesh.

    Blocking > Pre-Mesh

   Figure 132: Pre-Mesh After Adjusting the Boundary Layer

   
   
   

   In Figure 132: Pre-Mesh After Adjusting the Boundary Layer, initially there is uniformity and then the mesh size suddenly increases after a certain point. You will manually adjust edge parameters and use match edges to rectify this. This will also result in better quality.

Adjust the uniformity over the edges.

Blocking > Pre-Mesh Params   > Edge Params  

1. Select any radial edge as shown in Figure 133: Selected Edge.

   Figure 133: Selected Edge

   
   
   

   The arrow points inwards.

2. Set Spacing2 to 0.25 In the Meshing Parameters DEZ.

3. Enable Copy Parameters and select To All Parallel Edges in the Method drop-down list.

   This setting is copied to all the edges.

4. Click Apply.

5. Recompute the mesh.

   Figure 134: Pre-Mesh After Modifying Edge Parameters

   
   
   

   In Figure 134: Pre-Mesh After Modifying Edge Parameters, the distribution on the edges is much smoother now. However, there still is a slight jump around the center where the mesh size is considerably larger. You will use match edges to improve the mesh distribution.

Match the inward edges and outward edges to correct the jump in the midsection.

Blocking > Pre-Mesh Params   > Match Edges  

1. Select the Reference Edge and Target Edge as shown in Figure 135: Edges Selected for Match Edges.

   Figure 135: Edges Selected for Match Edges

   
   
   

   This will match the end spacing of the outer reference edge to the end spacing of the inner target edge. But only the selected radial edge is matched. You have to copy this to all the other edges.

2. Recompute the mesh.

3. Copy the spacing to all the other edges.

   Blocking > Pre-Mesh Params   > Edge Params  

   1. Click  (Select edge(s)) and select the matched edge.

   2. Ensure Copy Parameters is enabled and To All Parallel Edges is selected in the Method list.

   3. Click Apply.

   4. Recompute the mesh.

Check the quality of the mesh.

Blocking > Pre-Mesh Quality Histogram  

1. Ensure that Determinant 2x2x2 is selected in the Criterion drop-down list.

2. Retain 0 for Min-X value and 1 for Max-X value.

3. Retain 0 for Max-Y height and 20 for Number of bars.

4. Ensure that Only visible index range is disabled.

5. Enable Active parts only.

6. Click Apply.

7. Select the lower value bars to see the skewed cells (Figure 136: Worst Cells in the Pre-Mesh).

   Figure 136: Worst Cells in the Pre-Mesh

   
   
   

   You can see the improvement in mesh quality. The skewed cells are those which have a greater aspect ratio. You can reduce this by adjusting the nodes on the corresponding edge.

Improve the quality by adding elements in the direction of the skewed cells.

Blocking > Pre-Mesh Params   > Edge Params  

1. Select the edge near the skewed cells (see Figure 137: Edge Selected to Improve Quality).

   Figure 137: Edge Selected to Improve Quality

   
   
   

2. Increase the number of nodes to 20.

3. Ensure Copy Parameters is enabled and To All Parallel Edges is selected in the Method list.

4. Recompute the mesh.

5. Check the quality of the mesh.

   Blocking > Pre-Mesh Quality Histogram  

   1. Ensure that Determinant 2x2x2 is selected in the Criterion drop-down list.

   2. Retain 0 for Min-X value value and 1 for Max-X value value.

   3. Retain 0 for Max-Y height and 20 for Number of bars.

   4. Ensure that Only visible index range is disabled.

   5. Enable Active parts only.

   6. Click Apply.

   7. Select the lower value bars to see the skewed cells (Figure 138: Worst Cells After Adding Cells).

      Figure 138: Worst Cells After Adding Cells

      
      
      

      The element quality has improved and there are fewer elements in the lower bars of the histogram. The cells which now remain appear to have poor internal angles, and could be improved by adjusting the blocking to improve these angles. Adjusting the blocking too far could result in other cells (on the other side of the moved vertex) worsening. You could tweak to further improve this mesh, but it is more than high enough to give good results in any commercial solver. You will always have "worst elements", but if they are above the solver requirements, you can proceed. Typically, exceeding 0.1 for a determinant and 9 to 18 degrees for angle is sufficient.