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August 22, 2012, 08:34 
how to express a heat source term which depends on coordinate

#1 
New Member
kob
Join Date: Nov 2011
Posts: 28
Rep Power: 6 
Hello everyone
I am doing a heat transfer problem with source term. Source term itself depends on the x,y coordinates. The expression of the volumetric heat source is: Code:
when 0.2<x<0.2,0.3<y<0.3 q=20*exp(10*y) otherwise q=0 There is another question which is related to the x,y coordinate. Is it correct to express it like: Code:
volScalarField x = mesh.C().component(vector::X); volScalarField y = mesh.C().component(vector::Y); Code:
pos().x pos().y regards! bryant 

August 25, 2012, 07:37 

#2 
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kob
Join Date: Nov 2011
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Can you tell me about the above things if you know about that?
Thank you very much! regards! bryant 

April 7, 2013, 23:54 

#3 
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Neilson Whit
Join Date: Aug 2011
Location: Japan
Posts: 57
Rep Power: 7 
Dear bryant_k
did you find the solution? I am also working on it... pleased if you can inform me. 

April 8, 2013, 02:22 

#4 
Senior Member
Mohammad Shakil Ahmmed
Join Date: Oct 2012
Location: AUS
Posts: 129
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@ wolfindK
you can easily use funkySetFields utility, it's easy to apply, http://openfoamwiki.net/index.php/Co...funkySetFields 

April 9, 2013, 15:10 

#5 
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Daniel P. Combest
Join Date: Mar 2009
Location: St. Louis, USA
Posts: 581
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@wolfindark
Have you looked at using the new fvOptions capabilities? Here I have defined a source names "energySource1" with a time duration at a single point. The injection rate coefficients are specified as pairs of SuSp coefficients e.g. h (10 0) where the 10 is the explicit component and 0 is the implicit component. This is a linearized source term (read Patankar's book for more details and a source of this method) Code:
energySource1 { type scalarSemiImplicitSource; active true; timeStart 0.2; duration 2.0; selectionMode points; points ( (2.75 0.5 0) ); scalarSemiImplicitSourceCoeffs { volumeMode absolute; injectionRateSuSp { h (10 0); } } } Code:
$FOAM_SRC/fvOptions/sources/general/semiImplicitSource Last edited by chegdan; April 9, 2013 at 17:29. 

April 9, 2013, 22:57 

#6 
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Neilson Whit
Join Date: Aug 2011
Location: Japan
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Thank you chegdan,
For my case I needed a constant heat source, therefore, I used another method which was mentioned in this forum sometime ago. I just added explicit source term to temperature equation (in TEqn.H). Then I set the field values with setFields, a spherical heat source covering a particular region in fluid region. So it works fine until now. I am not sure but if time dependency is needed, it can be implemented in TEqn.H, What do you think..? 

April 10, 2013, 09:14 

#7  
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Daniel P. Combest
Join Date: Mar 2009
Location: St. Louis, USA
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Quote:


November 29, 2013, 07:19 

#8 
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Samuele Z
Join Date: Oct 2009
Location: Mozzate  Co  Italy
Posts: 490
Rep Power: 10 
Dear All,
pardon the interruption. I have a question about fvOption and I think you can help me. I would like to add a body force on certain cells. I have tried to write something like Code:
FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvOptions; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // momentumSource { type vectorExplicitSetValue; active on; //on/off switch selectionMode all; //cellSet // points //cellZone vectorExplicitSetValueCoeffs { injectionRate { F ( 0.1335 0 0 ); } } } Thanks a lot, Samuele 

December 1, 2014, 16:32 

#9 
New Member
zech
Join Date: Oct 2014
Location: Cambridge,England
Posts: 22
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Does scalarSemiImplicitSourceCoeffs{ h (10,0)} mean that the source is S=10+0*x, where S is the magnitude of the source and x is the coordinate. If that is true, then:
1.this method is applicable when the source is linearly related to the coordinate. What if it is not a linear function. Such as a cosine or experiential function? 2.Even worse, it is not even an function: it's just a matrix of random numbers. 3. what if the value is changing in both x and y direction? 

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