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Cold flow across a hot solid
Posted: 03 Apr 2019, 12:12
by kevinarden
Solid initial at 227 and fluid initial at 20. Body has a radiating boundary at 227. Inlet has 0 degree fluid. The initial condition looks as expected.
After the flow starts the 0 degree fluid is entering the inlet. However a cold region grows over the solid, foes to -200 degrees. Heat is seen radiating from the solid on the right side.
I did not expect this cold region to form, should it be expected?
- case.sif
- (4.15 KiB) Downloaded 278 times
Re: Cold flow across a hot solid
Posted: 03 Apr 2019, 12:13
by kevinarden
- mesh.zip
- (81.47 KiB) Downloaded 278 times
Re: Cold flow across a hot solid
Posted: 03 Apr 2019, 14:41
by mzenker
Hi,
AFAIK if radiation is involved all temperatures have to be in K.
HTH,
Matthias
Re: Cold flow across a hot solid
Posted: 04 Apr 2019, 00:02
by kevinarden
Converted the temperatures to Kelvin, same result, there is a cooling area above the hot solid, prior to the cold flow reaching it.
Re: Cold flow across a hot solid
Posted: 04 Apr 2019, 10:21
by dmitry
I have met the same troubles. It is numerical instabilities near high temperature gradient.
You can look here:
viewtopic.php?f=3&t=4164&p=14705#p14705
Peter gave me some tips. In fact, only mesh refining near the walls was resultative.
Re: Cold flow across a hot solid
Posted: 04 Apr 2019, 10:27
by dmitry
PS: I do not tried to play with Initial guess.
Re: Cold flow across a hot solid
Posted: 04 Apr 2019, 11:27
by kevinarden
Thanks, mesh refinement was my next step, and it resolved the problem.
Kevin