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Old   January 14, 2003, 08:40
Default nett source calculation
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Russ
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Can anybody please give me an explanation of how the nett sources are calculated in the results file. I have a formula of the sum of CO * ( VAL - VAR ) * "type multiplier". I am looking at an outlet and i'm unsure what values would be used for val and "tpye multiplier" in this case.

Thanks In Advance Russ
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Old   January 14, 2003, 13:13
Default Re: nett source calculation
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cham
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VAL will be the external pressure value, often zero, and the TYPE will be whatever appears in the Group 13 for this PATCH in the RESULT file, e.g. if VOLUME appears, then the cell volume is the multiplier. Thus, CO*(VAL-VAR)*VOLUME will be summed for all the cells in the PATCH, and the result printed in the RESULT file.

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Old   January 15, 2003, 09:44
Default Re: nett source calculation
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Russ
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I am trying to recreate how this is calculated for velocities at an outlet.

So my type multiplier is each cell area because the type is EAST.

If I look in Group 13 of the result file this tells me that CO and VAL are zero. COVAL(OB2 ,U1 , 0.000000E+00, 0.000000E+00)

Surely with the formula CO * ( VAL - VAR ) * "type multiplier" the nett sum would be zero.

Is it the same formula that is used or am I not understanding what numbers go into it?

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Old   January 16, 2003, 05:47
Default Re: nett source calculation
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cham
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The nett source for a generic variable F at an outlet boundary would be:

S = TYPE*(CMASS*(VMASS-Pp)+CPHI(F))*(VPHI(F)-Fp)

where Pp is the in-cell pressure, Fp is the in-cell value of F,and CMASS and VMASS are the CO and VAL for P1.
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