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Identity pairs, identity maps, continuity
Posted Feb 22, 2012, 8:36 a.m. EST Version 4.2 1 Reply
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Hello,
I'm using comsol 4.2 in 1D-PDE mode (weak form). My model is made of two domains( [O1 L1] and [O2 L2] ) on which are solved two different PDEs. There is only one variable for each PDE (u11 and u12).
In the attached mph file, there are 2 Dirichlet conditions at boundaries 1 and 4 and I would like to "link" the two domains by setting a "continuity" between boudaries 2 and 3 in order to have u11(L1)=u12(O2).
Do I have so set identity pairs or something else ?
Thank you,
I'm using comsol 4.2 in 1D-PDE mode (weak form). My model is made of two domains( [O1 L1] and [O2 L2] ) on which are solved two different PDEs. There is only one variable for each PDE (u11 and u12).
In the attached mph file, there are 2 Dirichlet conditions at boundaries 1 and 4 and I would like to "link" the two domains by setting a "continuity" between boudaries 2 and 3 in order to have u11(L1)=u12(O2).
Do I have so set identity pairs or something else ?
Thank you,
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1 Reply Last Post Feb 24, 2012, 2:37 a.m. EST
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Posted:
1 decade ago
Hi
what about taking a look at this thread, here we discuss something close ;)
www.comsol.eu/community/forums/general/thread/26354/#p71571
You have not yet understood the fields (les champs) variables versus global variables, this is somewhat confusing in COMSOL as the notation for a dependent variable is only u11, but it means in a 1D temporal case u11(x,t), and in fact most variables are ONLY defined as fields.
With your case of distinct domains and physics, and no "common boundary" (assembly OR Union mode is no difference in your case, a formula applying to all domains must contain only global cvariables, or links to fileds that have been madde global via an integration or average or other coupling operator.
The way to pick any value of a point, and to get it as a global variable is to define a variable as the integration over a single point, the integration operator then gives you the definition on where to load in the "x" spatial value, and the sum over a single point is the value AT the point (it's somewhat heavy, but mathematically correct, and compatible with the COMSOL notation logic)
--
Good luck
Ivar
what about taking a look at this thread, here we discuss something close ;)
www.comsol.eu/community/forums/general/thread/26354/#p71571
You have not yet understood the fields (les champs) variables versus global variables, this is somewhat confusing in COMSOL as the notation for a dependent variable is only u11, but it means in a 1D temporal case u11(x,t), and in fact most variables are ONLY defined as fields.
With your case of distinct domains and physics, and no "common boundary" (assembly OR Union mode is no difference in your case, a formula applying to all domains must contain only global cvariables, or links to fileds that have been madde global via an integration or average or other coupling operator.
The way to pick any value of a point, and to get it as a global variable is to define a variable as the integration over a single point, the integration operator then gives you the definition on where to load in the "x" spatial value, and the sum over a single point is the value AT the point (it's somewhat heavy, but mathematically correct, and compatible with the COMSOL notation logic)
--
Good luck
Ivar