Meshing ErrorMesh Size Approaching that Prescribed for Small Object Suppression

Mar 3, 2012


Issue:

To prepare the geometry for simulation, the user applies the Small Object Removal geometry tool to eliminate one or more tiny features. After starting the analysis, the initialization process stops during meshing, and the following error is issued:

Meshing Error: Mesh size approaching that prescribed for small object suppression for surface A near X Y Z (code 1106)

A is the surface ID; X, Y, and Z are the coordinates of the problem. (Note that the location may not always be provided.)

When Small Object Removal is applied, a geometric Tolerance is specified. Entities (usually edges, but some surfaces too) smaller than this are removed from the model so they are not meshed.

This error message attempts to identify the location of the problem with coordinates and an orange dot at the problem location.

This error occurs if the mesh size near the removed object is specified to be smaller than the object. There are a couple of ways this can happen:

  • After applying Automatic Mesh Sizing, the mesh size was refined on certain entities in the model (using the Size Adjustment slider). This error occurs if the refined element size near the removed entities is too close to the tolerance used in the Small Object Removal step.
  • The Minimum Refinement Length (on the Edge Diagnostics mode of the Mesh task) was set smaller than the tolerance used for Small Object Removal.

Solution:

Solution

1. Find the problem location.

  • The orange dot may be difficult to see, so turn off the mesh seed points to improve visibility. (From the menus at the top of the User Interface, click Window, and uncheck Show Mesh Seeds.)
  • Click the View as Outline icon to turn off all shading. This can really help you to see inside the model.
  • In some cases, an orange dot may not be displayed. It may be possible to find the location by examining the model with the mesh seeds enabled. Look for regions of densely clustered seeds. If the model is too complicated to find an issue, it may be necessary to increase the Minimum Refinement Length or coarsen the mesh (see the next steps).

2. Check the value of Minimum Refinement Length (MRL), and increase if necessary

  1. On the Mesh Sizes dialog, click the Diagnostics button.
  2. Select the Edge tab.
  3. If the MRL is smaller than the Tolerance applied for the Small Object Removal, increase its value. Be sure to use a value higher than the Small Object Removal Tolerance.

3. Check the mesh distribution near the removed objects, and coarsen if necessary.

  • Using the coordinates and orange dot as a guide, adjust the mesh to be coarser near the removed objects.
  • These may simply be one or more edges or it may be necessary to coarsen surfaces as well.

 

Products:

Simulation CFD

Versions:

2010;2011;2012;2013;2014

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