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BuoyantSimpleRadiationFoam Marshak BC

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Old   October 2, 2008, 10:06
Default dear all! i m about to stud
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Aram Amouzandeh
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dear all!

i m about to study the buoyantSimpleRadiationFoam solver and the appropriate tutorial case hotRadiationRoom. i found two different (marshak) bc for the variable G:

1) MarshakRadiation: Radiation temperature taken from calculated temperaure

2) MarshakRadiationFixedT: Radiation temperature specified

1) seems to be clear; for 2) a "radiation temperature" Trad needs to be specified, as an error message informed me, by the keywords "uniform" or "nonuniform":

type MarshakRadiationFixedT;
Trad nonuniform;
emissivity 1;
value uniform 0;

with this bc i get the following error message:

attempt to read beyond EOF

file: /home/E202/aa/OpenFOAM/aa-1.5.x/run/tutorials/buoyantSimpleRadiationFoam/hotRadi ationRoom/0/G::Trad at line 50.

From function ITstream::read(token& t)
in file db/IOstreams/Tstreams/ITread.C at line 64.

FOAM exiting

honestly i do not understand the MarshakRadiationFixedT bc, in other words i have no idea what Trad should be.

i would greatly appreciate any comments!!
thx in advance!
aram
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Old   October 2, 2008, 10:43
Default Try: type MarshakRadiationF
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Eugene de Villiers
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Try:

type MarshakRadiationFixedT;
Trad nonuniform 300;
emissivity 1;
value uniform 0;

Also, remember all temperatures are in Kelvin.
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Old   October 2, 2008, 12:29
Default thx eugene! i tried but get
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Aram Amouzandeh
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thx eugene!

i tried but get the same error message again. my main problem is that i have not been able to figure out the difference between the two Marshak bc yet ...

aram
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Old   October 2, 2008, 13:26
Default My mistake: type MarshakRad
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Eugene de Villiers
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My mistake:

type MarshakRadiationFixedT;
Trad uniform 300;
emissivity 1;
value uniform 300;

If you want to specify "nonuniform" it has to be followed by a list of values the size of the boundary, like:

value nonuniform List<scalar> (88 763 ... 789 423);
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Old   October 3, 2008, 07:03
Default ok, like this it works. now i
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Aram Amouzandeh
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ok, like this it works. now i can study the difference between the two bcs.

thanks a lot!

aram
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Old   October 3, 2008, 07:17
Default ok, like this it works. now i
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Aram Amouzandeh
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ok, like this it works. now i can study the difference between the two bcs.

thanks a lot!

aram
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Old   November 11, 2008, 07:25
Default Hi, i would like to use the
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Pattyn Eric
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Hi,

i would like to use the constant absorptionemission model (coefficients are present in my constant/radiationproperties file for a simple radiation case. Why this model is not present in OpenFoan-1.5/src/thermophysicalModels/radiation/radiationModel ? I just have P1, noreadiation and radiationModel directories.

I'm also wondering how the P1 model works. Is there any documentation i should read? I don't have see informations on thsi forum or in the user / Programmer's guide.

Thank you

Eric
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