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changing number of boundaries resulted from geometry deformation in the ALE mode
Posted Jan 13, 2010, 1:18 p.m. EST 4 Replies
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Hi everyone,
I am using 2D ALE module. my model is solved with a COMSOL script which force the solver to stop once the quality of mesh degrade below specified limit. After that I use mesh2geom command to recreate the geometry from deformed mesh and restart solver.
During the process of the geometry change one of the boundary lines shrinks gradually to a point and after that diminishes completely from my geometry. The change of geometry in my code can be just due to the change of the dimensions of the boundaries and diminishing one boundary from the geometry makes trouble in my code and it will stop due to an error.
Is there anyone who knows how I should deal with this problem?
I am thinking about making a new geometry when the mentioned boundary line becomes very small, map my previous results to the new geometry and continue to solve the problem, But I have following questions:
1) In the new geometry, I should merge the shrinking boundary with its nearby boundary. How can I do this?
2) How can I map my results from the previous geometry to the new one?
Thanks for your kind help,
Atieh
I am using 2D ALE module. my model is solved with a COMSOL script which force the solver to stop once the quality of mesh degrade below specified limit. After that I use mesh2geom command to recreate the geometry from deformed mesh and restart solver.
During the process of the geometry change one of the boundary lines shrinks gradually to a point and after that diminishes completely from my geometry. The change of geometry in my code can be just due to the change of the dimensions of the boundaries and diminishing one boundary from the geometry makes trouble in my code and it will stop due to an error.
Is there anyone who knows how I should deal with this problem?
I am thinking about making a new geometry when the mentioned boundary line becomes very small, map my previous results to the new geometry and continue to solve the problem, But I have following questions:
1) In the new geometry, I should merge the shrinking boundary with its nearby boundary. How can I do this?
2) How can I map my results from the previous geometry to the new one?
Thanks for your kind help,
Atieh
4 Replies Last Post Jan 15, 2010, 10:07 p.m. EST
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Posted:
1 decade ago
Hi
when your topology changs, COMSOl get lost, it cannot know what to do with the dissapearing subdomin and boundaries, and this will renumber the remaining ones. So from my knowledge you cannot solve problems where geoemtry dissapears, you have to find a way to keep it there but ignore it or make it "ransparent.
Hope this helps
Ivar
when your topology changs, COMSOl get lost, it cannot know what to do with the dissapearing subdomin and boundaries, and this will renumber the remaining ones. So from my knowledge you cannot solve problems where geoemtry dissapears, you have to find a way to keep it there but ignore it or make it "ransparent.
Hope this helps
Ivar
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Posted:
1 decade ago
Hi Ivar,
Thanks for your answer. today I received following answer from COMSOL support:
"you would need to do the following steps:
Run your 2D model with remeshing until the boundary is very small. Make sure you save all the data in a proper way (text file?), and map it on the geometry without the boundary. The challenging part is that you need to use GEOMANALYZE to keep track of the domains/boundaries when the topology changes. "
I have tough time to understand the way that I should deal with this problem. I will be thankful if you can help me more or send me an example using geomanalyze function in the ale mode.
Thanks,
Atieh
Thanks for your answer. today I received following answer from COMSOL support:
"you would need to do the following steps:
Run your 2D model with remeshing until the boundary is very small. Make sure you save all the data in a proper way (text file?), and map it on the geometry without the boundary. The challenging part is that you need to use GEOMANALYZE to keep track of the domains/boundaries when the topology changes. "
I have tough time to understand the way that I should deal with this problem. I will be thankful if you can help me more or send me an example using geomanalyze function in the ale mode.
Thanks,
Atieh
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Posted:
1 decade ago
Hi
Sorry to say, but I'm afraid I cannot help that much, last time I gave up when I had to deal with a topology change issue.
It is true that the "remesh" works fine when the volumes changes a lot, you can follow the subdomain volume by adding a subdomain integration variable of 1 and then decide for an action when it becoms smaller than a given value.
The geomanalyze allows you to find ways to track renumbering issues when items dissapear and you need to redefine them. But its rather complex for larger parts. Probably OK for a few items, at least you should start with only 2-3 items and then study their behaviour.
I believe you should consider to stop your study when the part becomes insignificant, and reconsider how best restart, perhaps even manually to begin with.
Good luck
Ivar
Sorry to say, but I'm afraid I cannot help that much, last time I gave up when I had to deal with a topology change issue.
It is true that the "remesh" works fine when the volumes changes a lot, you can follow the subdomain volume by adding a subdomain integration variable of 1 and then decide for an action when it becoms smaller than a given value.
The geomanalyze allows you to find ways to track renumbering issues when items dissapear and you need to redefine them. But its rather complex for larger parts. Probably OK for a few items, at least you should start with only 2-3 items and then study their behaviour.
I believe you should consider to stop your study when the part becomes insignificant, and reconsider how best restart, perhaps even manually to begin with.
Good luck
Ivar
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Posted:
1 decade ago
Thanks Ivar