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Old   April 25, 2001, 13:00
Default SOURCE TERM USER ROUTINE
  #1
Mario
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To add scalar source terms in the user-subroutine SORSCA, the source terms come in a linearized form: Source=S1P-S2P*Scalar(IS) To fix the source term to a given value, it is possible to introduce S1P=GREAT*VALUE, where great is a very large number (S2P has to be of character GREAT too). Does anyone know how to just add a value to a scalar, without fixing it to a value? I tried to use S1P without the Great and added a value to the scalar (S1P=SCALAR(IS)+VALUE), but a test showed that it didn`t work properly. Thanks for any suggestions. Regards Mario
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Old   April 26, 2001, 11:38
Default Re: SOURCE TERM USER ROUTINE
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Ossi
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Hi,

you should first activate the scalar you want to use and then activate the possibility that the scalar will have a source term (from the Analysis Controls/Miscellaneous Conntrols).

Then in the subroutine sorsca.f you should include an if-statement that questions what scalar is to have a source term, like e.g. if(IS.eq.11)then ... Do not include the scalar itself to the source term (SP1 or SP2) because it is already there if you use the linear term SP2 (remember, Source term = SP1 - SP2*scalar(11) !). Finally, make sure your units are right: the constant part SP1 has the units of your source term (e.g. kg/m3s) BUT the linear part's unit times that of the scalar's unit is equal to the source term unit (if you are dealing with a mass fraction, then the linear part has the unit of the constant part, e.g. SP1 - SP2*scalar(11) = [kg/m3s] - [kg/m3s]*[kg/kg], but the scalar needs not to be a mass fraction)

Regs.,

Ossi
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Old   April 26, 2001, 12:15
Default Re: SOURCE TERM USER ROUTINE
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Mario
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Hi Ossi,

I made the mistake to introduce S1P=SCALAR(1)+VALUE while S2P=1. I thought that if I would choose the VALUE as zero, in order to test the calculations, the results should be the same as if I would work without a subroutine. But I learned that the constant and linear parts are used in different iteration parts (inner and outer iterations) and that there is no need to use the scalar at the constant part.

Thanks for your response!! Regards Mario
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