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-   -   buoyantFoam OF15 very strange behaviour in hotRoom (https://www.cfd-online.com/Forums/openfoam-solving/58696-buoyantfoam-of15-very-strange-behaviour-hotroom.html)

andrea_barbera July 24, 2008 03:11
Dear OpenFOAM community, I'
 
Dear OpenFOAM community,

I'm a new OpenFOAM user and I hope that I will not make too many mistakes writing my first posts.

I have tried the tutorial hotRoom in the new release 1.5, and the behaviour of this case is different if compared to the one that we had in release 1.4.1: even if in the room there is only the usual hot source, at the end of the 400 seconds of simulation the mean temperature in the room is diminuished by 40 degress, and would continue to diminuish without reaching a steady state. The velocity field, however, seems correct according to me.

Is this only a large numerical error? And if it is, why it did not happen in release 1.4.1? Can someone help me to skip this problem?

Thanks

Andrea

mattijs July 25, 2008 09:59
Hi Andrea, Could be a bug i
 
Hi Andrea,

Could be a bug in 1.5. Can you post a bug report and we'll have a look at it.

andrea_barbera July 28, 2008 04:10
Hi Mattijs, I would post it
 
Hi Mattijs,

I would post it really with pleasure but, sincerely, I do not know what does it mean in detail. Have I only to report the involved files and the assignments used to run OpenFoam or it means something else, perhaps explained in some page that I did not found?

I'm sorry not to know this procedure, but I'm still a new user in this forum. I hope that I will learn as soon as possible!

thank you!

Andrea

mattijs July 28, 2008 05:23
Hi Andrea, http://www.openc
 
Hi Andrea,

http://www.opencfd.co.uk/openfoam/bugs.html.

(go to the OpenFOAM-bugs section and use the 'Bug report template' as a template to post a bug report. Most helpful to us)

waterboy July 30, 2009 09:06
buoyantFoam bug?
 
Have You found anything? A bug?
I have been trying to use buoyantFoam with FOAM version 1.5 or 1.5 dev, but it does't seem to make sense.
Setting all the walls to fixed temperature 300K and writing out thermo->T() I get
Quote:
Min(T) = 267.941 Max(T) = 600
at the last timestep 400s.
First timestep is OK with T between 300 and 600.
If using the original case the drop in minimum temperature is not as big but still there.
Since the air starts moving I believe the error is in thermo, it should get hotter in the room, or not?
Is there some BC issue I am missing?Should real air be defined differently?
The values in constant/thermophysical... seem all right to me
Quote:
mixture air 1 28.9 1000 0 1.8e-05 0.7;
pRef 1e5;
I hope someone comes up with the solution, the coarse mesh doesn't seem to be the main issue either...


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