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About Edge Vertex Distribution in Map Mesh
Posted Dec 30, 2009, 1:23 a.m. EST 5 Replies
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I'm now struggling to create 2D rectanglar mesh using map mesh option(COMSOL 3.2).
My geometry is arche (like rainbow).
I intend to make finer elements near inner boundary and coaser elements near outer boundary, and descend mesh element size from the inner one to the outer one gradually.
To accomplish this goal, I put "logspace(1,3,10)" in textbox in Edge Vertex Distribution in Map Mesh, for example. However, this generates an mesh which grows in opposite way (please see attached image).
I'm blocked now. I appriciate if you kindly tell me an appropriate way to create mesh which satisfies above goal. Thank you very much.
My geometry is arche (like rainbow).
I intend to make finer elements near inner boundary and coaser elements near outer boundary, and descend mesh element size from the inner one to the outer one gradually.
To accomplish this goal, I put "logspace(1,3,10)" in textbox in Edge Vertex Distribution in Map Mesh, for example. However, this generates an mesh which grows in opposite way (please see attached image).
I'm blocked now. I appriciate if you kindly tell me an appropriate way to create mesh which satisfies above goal. Thank you very much.
Attachments:
5 Replies Last Post Aug 27, 2010, 6:58 a.m. EDT
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Posted:
1 decade ago
Hi
If you are in the GUI you can select "Mapped Mesh Parameters - Boundary - Constrained edge elements distribution" put the desire number of elements, select an element ratio >1 and Distribution method: Exponential (you do notneed to use the Edge vertex distribution, but thats another way with a better finesse).
Now I beleive that you are being "fooled" by the direction vector, if you select edges they will appear with an arrow, this is the "positive" "s" parameter direction selected by COMSOL, it is done in a systematic way, but might appear upside down from the users view, you have to live with that, and if you select a quadrant of a cylindrical shell you will notice that the two edges that you want to have an exponential are most probably with opposite "signs". This means that you have to select each one individually and use the reverse direction on one of them, Murphy say that you will select the wrong one, when you have some choice, so if this happens its just to "EDIT undo mesh" and start again.
By the way you also have boundary mesh, that does something similar, but you end up with triangles at the opposed side, I use this sometimes, and then transform them into triangles with the appropriate command, if required
Hope this helps
Good luck
Ivar
If you are in the GUI you can select "Mapped Mesh Parameters - Boundary - Constrained edge elements distribution" put the desire number of elements, select an element ratio >1 and Distribution method: Exponential (you do notneed to use the Edge vertex distribution, but thats another way with a better finesse).
Now I beleive that you are being "fooled" by the direction vector, if you select edges they will appear with an arrow, this is the "positive" "s" parameter direction selected by COMSOL, it is done in a systematic way, but might appear upside down from the users view, you have to live with that, and if you select a quadrant of a cylindrical shell you will notice that the two edges that you want to have an exponential are most probably with opposite "signs". This means that you have to select each one individually and use the reverse direction on one of them, Murphy say that you will select the wrong one, when you have some choice, so if this happens its just to "EDIT undo mesh" and start again.
By the way you also have boundary mesh, that does something similar, but you end up with triangles at the opposed side, I use this sometimes, and then transform them into triangles with the appropriate command, if required
Hope this helps
Good luck
Ivar
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Posted:
1 decade ago
Thank you for your kind response.
Your suggestion is completely correctn the "direction arrow" of my boundary seems the point of issue.
So, I tried to select "reverse direction" check box to let the distribution reversed.
However, I coudn't find this option in "map mesh" dialog. Probably, this is because of COMSOL version because I can find the discription about "reverse direction" check box when I looked up COMSOL 3.5a version manual, whereas no findings for that of COMSOL 3.2 version. I'm up against the wall and maybe the only option seems upgrading my COMSOL. Thank you.
Your suggestion is completely correctn the "direction arrow" of my boundary seems the point of issue.
So, I tried to select "reverse direction" check box to let the distribution reversed.
However, I coudn't find this option in "map mesh" dialog. Probably, this is because of COMSOL version because I can find the discription about "reverse direction" check box when I looked up COMSOL 3.5a version manual, whereas no findings for that of COMSOL 3.2 version. I'm up against the wall and maybe the only option seems upgrading my COMSOL. Thank you.
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Posted:
1 decade ago
Hi
Well if you uppgrade, think of V4 coming these days, its a rather large step in changes as the interfaces has been switched, but after some explanations on the reasons why, ad having tested it during a few days, I must admit I was rather entousastic, furthermore many of the issues that made remodelling touh has bee hihgly improved, including history of meshiong process.
by the way, try to give a progression with a minus sign on one of the edges, perhaps that does it
Good luck
Ivar
Well if you uppgrade, think of V4 coming these days, its a rather large step in changes as the interfaces has been switched, but after some explanations on the reasons why, ad having tested it during a few days, I must admit I was rather entousastic, furthermore many of the issues that made remodelling touh has bee hihgly improved, including history of meshiong process.
by the way, try to give a progression with a minus sign on one of the edges, perhaps that does it
Good luck
Ivar
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Posted:
1 decade ago
Thank you for your reply.
Based on your suggestion,
I tried to put "-logspace(1,3,10)" in textbox in Edge Vertex Distribution in Map Mesh, but this gives an error...
By the way, I realized that I can obtain my goal by putting like "0, 0.1, 0.2, 0.4, 0.8" for one boundary and " 0, 0.4, 0.6, 0.7, 0.8" for the other arrow-reversed boudary.
Anyway, for more convenient, I'll check features of the latest version of COMSOL.
Based on your suggestion,
by the way, try to give a progression with a minus sign on one of the edges, perhaps that does it
I tried to put "-logspace(1,3,10)" in textbox in Edge Vertex Distribution in Map Mesh, but this gives an error...
By the way, I realized that I can obtain my goal by putting like "0, 0.1, 0.2, 0.4, 0.8" for one boundary and " 0, 0.4, 0.6, 0.7, 0.8" for the other arrow-reversed boudary.
Anyway, for more convenient, I'll check features of the latest version of COMSOL.
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Posted:
1 decade ago
Hello;
I've been recently used Comsol Multhyphysics 3.4. I encounter more or less the same problem. I want to seperate my rectangular 2D axial symmettric geometry into meshes which are intenser at each individual boundaries. When I use mapped mesh parameters I specify element ratio, number of elements and distrubition (linear or exponential). But I can only get intenser meshes at 2 out of 4 boundaries.(see attached file) could you please help me to achieve this.
Thanks in advance
Best Regards
I've been recently used Comsol Multhyphysics 3.4. I encounter more or less the same problem. I want to seperate my rectangular 2D axial symmettric geometry into meshes which are intenser at each individual boundaries. When I use mapped mesh parameters I specify element ratio, number of elements and distrubition (linear or exponential). But I can only get intenser meshes at 2 out of 4 boundaries.(see attached file) could you please help me to achieve this.
Thanks in advance
Best Regards
Attachments: