Node layer number result

Solver messages that report insufficient mesh refinement through a 3D part can be investigated using the Node layer number result.

When generating the 3D mesh for a model, the geometry of the part, or the coarseness of the Dual Domain mesh it was based on, can result in areas of the model with less than the expected number of layers in the tetrahedral mesh. Analyses will still run, but solution accuracy may be reduced.

The Node layer number result represents the structure of the mesh within a model by displaying the number of node layers through the thickness of the part.

Note:

• Node layer number result is not a default result. To access this result, right click on Flow in the Study Task pane and select New Plot. Scroll down the available results, select Node layer number from the list and select OK.
• When you generate a mesh, you specify the desired number of elements and not the number of nodes through the thickness. The nodes on the surface of the model are included in the result. Because of this, a model with six layers of elements will have seven node layers.

Using this result

Node layers are assigned a value, starting with the outer surface of the part having a value of 1, and increasing towards the middle of the part. The node layer number in the middle of the part is a representation of the refinement of the mesh at that point.

The anticipated value of the middle node layer can be determined by the following formula:

Where

• N is the number of tetrahedral layers at that model location.
• n is the value of the node layer

For a model with 6 tetrahedral layer elements through the part, the middle node layer will have a value of 4.

Areas with insufficient node layers can be located by using either a cutting plane or filtering the plot to display the middle node layer value.

Using a cutting plane

With the Node layer number result active, click (View tab > Cutting Plane panel > Edit) to create a cutting pane. Move the cutting plane to investigate the level of refinement in the area of interest.

Filtering the plot

With the Node layer number result active, right-click on the result name and select Properties. Select the Scaling tab. Click Specified and define the range of layers to be viewed. If the middle layer value expected is 4, filter between 3.5 and 4.5. Ensure the Extended color check-box is not selected.

Areas of the model with less than the required number of layers will appear as gaps in the result.

Because the node layer numbering starts at the edge of the part, it is normal for plate-like areas to have blank borders around the edge. This is a function of how the result is generated and may not be an indication of localized insufficient refinement.

Things to look for

If any areas with less than the required number of node layers correspond with a critical feature of the model, consider the following alternatives:

• Click (Mesh tab > Mesh Repair panel > Remesh Tetras) to refine the mesh in the local area.
• Convert the model to a Dual Domain mesh, re-mesh the part with a reduced global edge length and then convert the model back to a 3D mesh.

Re-run the analysis after re-meshing the part to ensure the model now has adequate refinement.