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heat flux on boussinesq

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Old   December 11, 2011, 13:18
Default heat flux on boussinesq
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Dear Foam's,

Im trying to set heat flux as a boundary condition of my buoyantboussinesqSimpleFoam case. But my solution is too dependent of the mesh resolution, as I refine my mesh the final temperature of the fluid descreases each time more.

Qflux = k*(gradT)
gradT = qflux/k ; k=0,17 , Qflux = 10000

so Im setting in the T file :

fixedWalls
{
type fixedGradient;
gradient uniform 58823;
}

Can anyone tell me what am I doing wrong ?

Thanks for the attention.
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Old   December 11, 2011, 13:19
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(Im considering K constant...)
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Old   December 12, 2011, 03:27
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does the temperature become less than the temperature that you calculate with the a simple heat balance?

what kind of turbulence modeling do you use?
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Old   December 12, 2011, 07:05
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Yes, it become less then that i calculated with simple heat balance as I refine mesh.

Its a laminar flow.
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Old   December 12, 2011, 07:11
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Quote:
Originally Posted by Andrev View Post
Yes, it become less then that i calculated with simple heat balance as I refine mesh.

Its a laminar flow.
what kind of geometry are we talking about, what is your yPlus of your first cell and what kind of fluid do u treat (Pr = 1, Pr > 1 or Pr < 1)
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Old   December 12, 2011, 07:23
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Its a simple rectangular channel section flow with constant heatflux on the fixed walls (4 walls), ethanol is the fluid (Pr ~ 16.5).
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