ElmerGrid help with defining boundaries

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rgladstone
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Joined: 15 Apr 2013, 16:23
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ElmerGrid help with defining boundaries

Post by rgladstone »

Hi all, I have a vertically extruded mesh (created for ice sheet modeling using extrudemesh) based on a 2D unstructured mesh with mainly (entirely?) triangular elements. I wish to label the intersection of the bed (boundary 1) and the side walls (boundaries 3 and 4) as a new boundary. I am trying this using the "-boundbound" option with ElmerGrid (see code below). It either runs very slowly or else it is stuck in an infinite loop, because the "FindNewBoundaries: not implemented for all 3d boundaries" messages are gradually accruing.

Can someone tell me the significance of "FindNewBoundaries: not implemented for all 3d boundaries"? Is it not successful for certain boundary types? What does this depend on, element type? Or does this message mean there is something wrong with my mesh?

Is there a good way to visualise the boundaries in the resulting mesh? I mainly use Paraview for visualising Elmer outputs, but I don't know if it can be used to look at mesh boundaries. When checking simple meshes I usually just look at the text files mesh.boundary, but this is not so practical for larger files. Perhaps I need to use ElmerPost? Is there documentation for ElmerPost? I've not found any yet.

Thank you very much for your help,
Rupert

Code: Select all

ElmerGrid 2 2 ASFic3_B3_v2_2 -out ASFic3_B3_v2_2b -boundbound 3 1 7 -boundbound 4 1 7

Starting program Elmergrid
Elmergrid reading in-line arguments
Output will be saved to file ASFic3_B3_v2_2b.

Elmergrid loading data:
-----------------------
Loading mesh in ElmerSolver format from directory ASFic3_B3_v2_2.
Loading header from mesh.header
Maximum elementtype index is: 706
Allocating for 37576 knots and 61320 elements.
Loading 37576 Elmer nodes from mesh.nodes
Loading 61320 bulk elements from mesh.elements
Loading 19244 boundary elements from mesh.boundary
All done

Elmergrid creating and manipulating meshes:
-------------------------------------------
Finding nodes between boundary elements of type 3 and 1
There are from 0 to 4 hits per node
Located 698 nodes at the interval between boundaries 3 and 1
There are 698 nonzero entries in boundnodes vector!
FindNewBoundaries: not implemented for all 3d boundaries
FindNewBoundaries: not implemented for all 3d boundaries
FindNewBoundaries: not implemented for all 3d boundaries
FindNewBoundaries: not implemented for all 3d boundaries
FindNewBoundaries: not implemented for all 3d boundaries
raback
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Re: ElmerGrid help with defining boundaries

Post by raback »

Hi Rupert

I strongly encourage you to use the internal extrusion features of ElmerSolver. The "boundbound" type of features are not really the focus of current development. The internal extrusion also avoids many bottlenecks if the goal is to do some seriously large computations.

You can set for VTU output an option to save the IDs:
Save Geometry Ids = Logical True

There is no manual on ElmerPost. There is a slide show that illuminates how to do the same things in ElmerPost/Paraview:
http://www.nic.funet.fi/pub/sci/physics ... August.pdf

-Peter
rgladstone
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Joined: 15 Apr 2013, 16:23
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Re: ElmerGrid help with defining boundaries

Post by rgladstone »

Thank you for the information Peter,

I think Thomas plans to introduce us to the internal mesh update this weekend, so I'll see if my question about boundary labelling can be answered then.

Cheers,
Rupert
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