BuoyantSimpleRadiationFoam Marshak BC

mabinty · October 2, 2008, 10:06

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

eugene · October 2, 2008, 10:43

Try:

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

Also, remember all temperatures are in Kelvin.

mabinty · October 2, 2008, 12:29

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

eugene · October 2, 2008, 13:26

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);

mabinty · October 3, 2008, 07:03

ok, like this it works. now i can study the difference between the two bcs.

thanks a lot!

aram

mabinty · October 3, 2008, 07:17

ok, like this it works. now i can study the difference between the two bcs.

thanks a lot!

aram

ep4 · November 11, 2008, 07:25

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

October 2, 2008, 10:06	dear all! i m about to stud	#1
mabinty Senior Member Aram Amouzandeh Join Date: Mar 2009 Location: Vienna, Vienna, Austria Posts: 190 Rep Power: 17	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

October 2, 2008, 10:43	Try: type MarshakRadiationF	#2
eugene Senior Member Eugene de Villiers Join Date: Mar 2009 Posts: 725 Rep Power: 21	Try: type MarshakRadiationFixedT; Trad nonuniform 300; emissivity 1; value uniform 0; Also, remember all temperatures are in Kelvin.

October 2, 2008, 12:29	thx eugene! i tried but get	#3
mabinty Senior Member Aram Amouzandeh Join Date: Mar 2009 Location: Vienna, Vienna, Austria Posts: 190 Rep Power: 17	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

October 2, 2008, 13:26	My mistake: type MarshakRad	#4
eugene Senior Member Eugene de Villiers Join Date: Mar 2009 Posts: 725 Rep Power: 21	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);

October 3, 2008, 07:03	ok, like this it works. now i	#5
mabinty Senior Member Aram Amouzandeh Join Date: Mar 2009 Location: Vienna, Vienna, Austria Posts: 190 Rep Power: 17	ok, like this it works. now i can study the difference between the two bcs. thanks a lot! aram

October 3, 2008, 07:17	ok, like this it works. now i	#6
mabinty Senior Member Aram Amouzandeh Join Date: Mar 2009 Location: Vienna, Vienna, Austria Posts: 190 Rep Power: 17	ok, like this it works. now i can study the difference between the two bcs. thanks a lot! aram

November 11, 2008, 07:25	Hi, i would like to use the	#7
ep4 Member Pattyn Eric Join Date: Mar 2009 Posts: 61 Rep Power: 17	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