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Inconsistency of the weak term units ?!
Posted Apr 6, 2010, 12:35 p.m. EDT 3 Replies
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My weak term for a boundary application mode does not have a right unit (red brackets if i write it in the scalar expressions):
test(phix)*1/R*phix + test(phi)*Jb
Should I always ignore the units of the weak terms?
From the starting equation
nabla Gamma = F , unit[Gamma] = A/m , unit[F] = A/m^2
follows unit[Gamma] is not equal unit[F] and
unit[ test(phix)*1/R*phix] is not equal unit[ test(phi)*Jb] ???
=> It is not possible to have a right unit for the weak term !??
Or should i use the unit 1 for the weak term:
test(phix/1[V/m])*1/R*phix/1[A/m] + test(phi/1[V])*Jb/1[A/m^2]
Maybe I have still an error in my weak term?
I do not like the inconsistency of the units...
Edit:
The unit of the weak term example
Ds*(-test(csTx)*csTx-test(csTy)*csTy)+test(cs)*(react_surf-cst)
in the "Transport and Adsorption" model is also not ok.
test(phix)*1/R*phix + test(phi)*Jb
Should I always ignore the units of the weak terms?
From the starting equation
nabla Gamma = F , unit[Gamma] = A/m , unit[F] = A/m^2
follows unit[Gamma] is not equal unit[F] and
unit[ test(phix)*1/R*phix] is not equal unit[ test(phi)*Jb] ???
=> It is not possible to have a right unit for the weak term !??
Or should i use the unit 1 for the weak term:
test(phix/1[V/m])*1/R*phix/1[A/m] + test(phi/1[V])*Jb/1[A/m^2]
Maybe I have still an error in my weak term?
I do not like the inconsistency of the units...
Edit:
The unit of the weak term example
Ds*(-test(csTx)*csTx-test(csTy)*csTy)+test(cs)*(react_surf-cst)
in the "Transport and Adsorption" model is also not ok.
3 Replies Last Post Apr 8, 2010, 1:55 a.m. EDT
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Posted:
1 decade ago
I'm not sure if it will help you, but this is a quote from Tubular reactor model:
Because Tc is the dependent variable of a PDE application mode, it does not have an associated unit. Therefore, if the Highlight unexpected units check box is selected in your modeling session, the Unit label for the q0 edit field appears in red. Provided you specify the boundary condition for Tc using the chosen base unit system (specified under Physics>Model Settings; the default choice is SI), you can safely ignore this warning.
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Posted:
1 decade ago
Hi
in V3.5a the units are not fully ported all over, i.e. integration coupling variables are not ported with units, probably the test functions neither, I hadnt really realised.
I like the units feature as it helps a lot for the debugging, but a red unit warning remains a warning and might be fully "legal" specially if you use items such as integration coupling variables, and now I should add test functions
have fun Comsoling
Ivar
in V3.5a the units are not fully ported all over, i.e. integration coupling variables are not ported with units, probably the test functions neither, I hadnt really realised.
I like the units feature as it helps a lot for the debugging, but a red unit warning remains a warning and might be fully "legal" specially if you use items such as integration coupling variables, and now I should add test functions
have fun Comsoling
Ivar
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Posted:
1 decade ago
Ok. Thank you for your replies!