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Can Comsol solve two physics with a common variable together?
Posted May 9, 2016, 3:32 p.m. EDT Studies & Solvers Version 5.2 1 Reply
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Hello
I am trying to couple Heat Transfer and Transport of Concentrated Species together. They both have a common variable dependency. I have to put a mass flux in a water-air interface and, the mass flux will take some heat away from the evaporation, which I have added to my heat transfer physics as a heat source. The flux is a function of temperature and partial vapor pressure. Temperature can be calculated by heat transfer physics. However, to calculate the partial vapor pressure I have to use the Transport of Concentrated Species to find the mass fraction of water in air domain. This is how my Heat Transfer and Species Transport physics in coupled. But when I try to do that, Comsol is giving an error of "Circular variable dependency detected".
So comsol cannot solve two inclusive physics together?
I am trying to couple Heat Transfer and Transport of Concentrated Species together. They both have a common variable dependency. I have to put a mass flux in a water-air interface and, the mass flux will take some heat away from the evaporation, which I have added to my heat transfer physics as a heat source. The flux is a function of temperature and partial vapor pressure. Temperature can be calculated by heat transfer physics. However, to calculate the partial vapor pressure I have to use the Transport of Concentrated Species to find the mass fraction of water in air domain. This is how my Heat Transfer and Species Transport physics in coupled. But when I try to do that, Comsol is giving an error of "Circular variable dependency detected".
So comsol cannot solve two inclusive physics together?
1 Reply Last Post May 10, 2016, 1:31 a.m. EDT
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Posted:
9 years ago
Hi,
This error message appears when a variable is used to define itself, v=f (s, t, v,...). There are many threads about this on the forum.
Basically there are two ways of resolving this problem:
a) Reformulate so that v=g(s, t, ...) . Sometimes this is easy, sometimes it is not possible.
b) Introduce an extra intermediate dependent variable in the problem, so that v=f (s, t, v2, ...) and v2=v. An example of this can be found in
www.comsol.com/model/modeling-stress-dependent-elasticity-14441
Regards,
Henrik
This error message appears when a variable is used to define itself, v=f (s, t, v,...). There are many threads about this on the forum.
Basically there are two ways of resolving this problem:
a) Reformulate so that v=g(s, t, ...) . Sometimes this is easy, sometimes it is not possible.
b) Introduce an extra intermediate dependent variable in the problem, so that v=f (s, t, v2, ...) and v2=v. An example of this can be found in
www.comsol.com/model/modeling-stress-dependent-elasticity-14441
Regards,
Henrik