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Element refinement in Plot Parameters

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I am curious about the Element refinement setting on the General tab of Postprocessing Plot Parameters. In plotting the mesh along with the solution (Knowledge Base 1003), unchecking Auto under Element refinement and entering 1 into the value box, I see what I believe is the actual mesh at my desired location within my 3D solid. If I plot with Auto checked, the resulting mesh is much finer. Could someone explain what COMSOL is doing here?

Mike

2 Replies Last Post 18 nov. 2009 à 23:30 UTC−5

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Posted: 10 years ago 18 nov. 2009 à 16:37 UTC−5
Hi

from what I have got explained (but I havn't realy gone into the details myself), the Postprocessing refinement is the order of the polynomials used to smoothen your results. The FEM methode only gives you correct values on the nodes, so to show results in between you must extrapolate, or interpolate beween the nodes.

With refinement = 1 you have the raw "data on nodes" mode and I believe indeed the line you see are the meshing.

Normally by selecting "higer order" elements types you also increase the order of "internal" nodes used between the true geometrical points/nodes when solving, this increases the memory requirements, but you get better precision on your results.

Run and indexed search on your doc files and search for "refinement" you will find more therein

Good luck
Ivar
Hi from what I have got explained (but I havn't realy gone into the details myself), the Postprocessing refinement is the order of the polynomials used to smoothen your results. The FEM methode only gives you correct values on the nodes, so to show results in between you must extrapolate, or interpolate beween the nodes. With refinement = 1 you have the raw "data on nodes" mode and I believe indeed the line you see are the meshing. Normally by selecting "higer order" elements types you also increase the order of "internal" nodes used between the true geometrical points/nodes when solving, this increases the memory requirements, but you get better precision on your results. Run and indexed search on your doc files and search for "refinement" you will find more therein Good luck Ivar

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Posted: 10 years ago 18 nov. 2009 à 23:30 UTC−5
Thanks Ivar. I suspected the refinement was something like this but couldn't find an authoritative answer. It is my thinking that with a refinement of 1, the values at the nodes match (adjacent elements sharing the same node), but the curve will not be continuous. Increasing element refinement approaches a continuous curve connecting the nodes.

Mike
Thanks Ivar. I suspected the refinement was something like this but couldn't find an authoritative answer. It is my thinking that with a refinement of 1, the values at the nodes match (adjacent elements sharing the same node), but the curve will not be continuous. Increasing element refinement approaches a continuous curve connecting the nodes. Mike

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