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Sure, there is definitly a better way.

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Sure, there is definitly a better way.

Posted November 22, 2012 at 13:09 by diamondx

Originally Posted by PSYMN View Post
Yes, of course, a better surface mesh leads to a better volume mesh.

I go to the smooth or mesh quality and run my check… This creates a histogram in the bottom right corner. You can adjust the range of the histogram if it is too hard to see the lowest columns. Left click on columns to display the mesh from each column on the screen (track lightly as this may be memory/display intensive). Right click on the histogram to create a subset of the elements in the highlighted columns… Then go over to the model tree. Under the mesh branch, you will find a subset branch. Turn off the shells and other ways mesh is displayed and just display the subset. These are the elements of that histogram bar (or however many bars were highlighted when you created the subset). Right click on the subset and “add to subset”, this will add attached surface elements. You can have other options if you chose to "modify" the subset. "Add to subset" a few times until you get enough elements to understand the situation. Most can be fixed by either adjusting node projection, merging away sliver nodes, splitting edges, or swapping edges. Move nodes may also help.

After fixing up an area, right click on subset again and choose "remove from subset", then remove the area you repaired. This just helps to clean up what you are looking at so you can focus on the remaining clumps.

Removing a subset does not delete the mesh, it is just a display trick.

I usually also use Check mesh and create subsets to find single and multiple edges, non manifold verts, etc.

After you have made all your fixes, run the smooth again and create another histogram...

This may be a somewhat iterative process, but don't let it make you crazy. There is always a worst element and you may need to say, "that is just the best element that will fit in there due to my geometry constraints". Your solver can handle it (most of the time). If 0.3 is the goal for Fluent, you can probably handle a few between 0.01 and 0.3.

Also, when you get to Prisms, expect they will have lower quality, but down to 0.01 is usually fine for Fluent.
Simon's tips...
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