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Temperature discrepancy

Posted Nov 20, 2012, 10:39 a.m. EST Heat Transfer & Phase Change Version 4.3 4 Replies

SMHH
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Hi,

I am modeling a simple conduction problem in solids. When I model my geometry as a unified body, I get a maximum temperature of 358. But when I split my geometry into subdomains and define a heat transfer in solid for each of them, I get 362 for maximum temperature! I think that the problem lies in how comsol treats the common boundary between subdomains. If it assigns a coupled temperature to these boundaries, the result for two simulations should be similar. Any ideas about this issue?

Thanks.
4 Replies Last Post Nov 21, 2012, 1:36 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 20, 2012, 12:56 p.m. EST
Hi

if noting else is wrongly set up in sucha simple or triple model, from my knowledge the only difference will be the mesh density, and a few degrees difference is often due to mesh density issues, are you sure you have a reasonable mesh density that is comparable or at least that each calculation is mesh independent ?

--
Good luck
Ivar
Hi if noting else is wrongly set up in sucha simple or triple model, from my knowledge the only difference will be the mesh density, and a few degrees difference is often due to mesh density issues, are you sure you have a reasonable mesh density that is comparable or at least that each calculation is mesh independent ? -- Good luck Ivar
SMHH
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Posted: 1 decade ago Nov 21, 2012, 5:38 a.m. EST
Hi Ivar,

Thanks for the reply. Actually the first thing that came into my mind was the mesh size. I refined the mesh in both cases using extremely fine option. But the difference is still the same (362-358 = 4). Thus, it should not be the problem!

Mohammad
Hi Ivar, Thanks for the reply. Actually the first thing that came into my mind was the mesh size. I refined the mesh in both cases using extremely fine option. But the difference is still the same (362-358 = 4). Thus, it should not be the problem! Mohammad
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 21, 2012, 1:11 p.m. EST
Hi

next is where is the maximum, is it a local point or an average value, often you have some "hotspots" that are wrong, depending on BC or other model set up, but 99.99% of the rest of the model is identical, could it be that ?

--
Good luck
Ivar
Hi next is where is the maximum, is it a local point or an average value, often you have some "hotspots" that are wrong, depending on BC or other model set up, but 99.99% of the rest of the model is identical, could it be that ? -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Nov 21, 2012, 1:36 p.m. EST
If your models are not confidential post them on the Forum and someone (Ivar most likely!) can take a look and give you a definitive answer.
If your models are not confidential post them on the Forum and someone (Ivar most likely!) can take a look and give you a definitive answer.

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