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Names of variables and Partial differential in COMSOL v4.2

Posted Mar 1, 2012, 11:43 a.m. EST Parameters, Variables, & Functions Version 3.5a, Version 4.2 2 Replies

Zhangxian Deng
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Hi,

I set up a PDE model in COMSOL v4.2
PDEs (Weak Form):
Dependent Variables: AX, AY, AZ

Global Definition - Variable :
BX = AZy - AYz;

Weak Expression:
-HX*test(BX)+JX*test(AX); (HX and JX have been defined)

Error: Unknown variable AZy.

In COMSOL v3.5, AZy means "(partial AZ)/(partial y)". However, it seems that COMSOL 4.2 regards "AZy" as a new variable but not a differetial notation.

How to define a partial differential operator in COMSOL 4.2? Are there any restrictions of the names of dependent variables?

Thanks a lot.

Dan
2 Replies Last Post Mar 1, 2012, 4:14 p.m. EST
Zhangxian Deng
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Posted: 1 decade ago Mar 1, 2012, 2:29 p.m. EST
I've figured out the problem:

Capital "X" "Y" "Z" are not proper name for variables.
I've figured out the problem: Capital "X" "Y" "Z" are not proper name for variables.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 1, 2012, 4:14 p.m. EST
Hi

many names has changed in V4 so it's worth to turn on the "Equation View (Options Preferences Show) and look therein.
But you can also load the intial conditions (right click solver sub-node: Dependent Variables and choose "Compute to Selected", and then hit the Derived Values Integration and use the variable selector (or CNTRL + Space)

There its written too that the gradient is AXx, AXy, AXz, etc so this has not changed ;)

So you must have something else that went wrong

--
Good luck
Ivar
Hi many names has changed in V4 so it's worth to turn on the "Equation View (Options Preferences Show) and look therein. But you can also load the intial conditions (right click solver sub-node: Dependent Variables and choose "Compute to Selected", and then hit the Derived Values Integration and use the variable selector (or CNTRL + Space) There its written too that the gradient is AXx, AXy, AXz, etc so this has not changed ;) So you must have something else that went wrong -- Good luck Ivar

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