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circular variable dependency detected

Posted Jul 10, 2012, 4:37 p.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD), Mesh, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 5.0, Version 5.2a 4 Replies

Susant Patra
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Hi,

The author of one paper has defined the conductivity as a function of current density and current density as a function of conductivity. In comsol, it gives a circular dependency error. How to get around it? I would appreciate any suggestion in this regard.

Regards,
Susant
4 Replies Last Post Jun 4, 2017, 6:56 p.m. EDT
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Hello Susant Patra

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Chandan
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Posted: 1 decade ago Aug 11, 2014, 4:20 a.m. EDT
Hi,
I am having same problem. Have you solved the problem ?

Chandan Kumar
Hi, I am having same problem. Have you solved the problem ? Chandan Kumar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Aug 11, 2014, 10:48 a.m. EDT
There are two ways around this. If you can do some algebraic manipulations you may be able to get the conductivity and current density equations decoupled. If you cannot do that then define a new Domain ODE that breaks that circular dependency. The ODE can just involve one variable that you set equal to the current density and use that new variable in the definition of the conductivity.

Nagi Elabbasi
Veryst Engineering
There are two ways around this. If you can do some algebraic manipulations you may be able to get the conductivity and current density equations decoupled. If you cannot do that then define a new Domain ODE that breaks that circular dependency. The ODE can just involve one variable that you set equal to the current density and use that new variable in the definition of the conductivity. Nagi Elabbasi Veryst Engineering
剑华 邵
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Posted: 8 years ago Jun 12, 2016, 3:04 a.m. EDT
Hi，I am new to COMSOL. I had the same problem. Can you give a simple sample with second method(ODEs)? Thank you very much! My email is njutsjh@163.com.


Jianhua Shao
Hi，I am new to COMSOL. I had the same problem. Can you give a simple sample with second method(ODEs)? Thank you very much! My email is njutsjh@163.com. Jianhua Shao
Antonino Amoddeo
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Posted: 7 years ago Jun 4, 2017, 6:56 p.m. EDT
Hi,
I'm implementing a moving mesh in a 2D model with five dependent variables, imposing the 'prescribed deformation' in the domain with 'prescribed mesh displacement' dx = u1x and dy = u1y, but I get the following error message: circular variable dependency detected. Please, could you be more specific about the suggestion in your response of August 11 2014?
Thank you
Hi, I'm implementing a moving mesh in a 2D model with five dependent variables, imposing the 'prescribed deformation' in the domain with 'prescribed mesh displacement' dx = u1x and dy = u1y, but I get the following error message: circular variable dependency detected. Please, could you be more specific about the suggestion in your response of August 11 2014? Thank you

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