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Tadiwos August 10, 2001 03:57

Boundary declaration

I am simulating a ventillated installation with heat transfer and k-epsilon model. I imposed a boundary condtion with a certain outer temperature. But I saw a very funny result on the post processer. The whole layer of cell at the boundary has the same temperature. Is this because my grid is course? or there is something wrong due to other reasons.How does CFX4.3 understands boundary? Is it an infinitisimal outer face or the whole cubic cell at the pheriphery of the room?



Astrid August 10, 2001 06:29

Re: Boundary declaration
A long time ago, someone told me that in such a case you might be looking at the ambient temperature. Is this the value you see? (I might be wrong, it is approx. 4 years ago........). Are you using CFX-Visualise on a Unix machine?


Tadiwos August 10, 2001 08:12

Re: Boundary declaration
Dear astrid

I use cfx visualise on the unix machine, and you are right i see the ambient temperature but what confused me is that how can it be the whole boundary cells have constant temperature?

Thanks Astrid


Astrid August 10, 2001 16:55

Re: Boundary declaration
I don't exactly remember why you see the ambient temperature. There was something wrong and AEA was to blame. Perhaps you can try CFX-View or CFX-Analyse to check if you have implemented physics correctly. Or write out some values over a line to a file in CFX-Visualise. I did a check with Userfortran and found out that tempratures were OK.

Good luck

Dave August 22, 2001 09:12

Re: Boundary declaration
Is this a hybrid / conservative result set issue ?? I'm not sure about this, but it may be worth having a look at the dirrefence between the results. You can load the conservative results by choosing the option in the Load Files option of visualise (CFX5). Good luck Dave

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