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-   -   No Convection/Diffusion: CFX4 (https://www.cfd-online.com/Forums/cfx/21656-no-convection-diffusion-cfx4.html)

Robin K September 28, 2005 16:52

No Convection/Diffusion: CFX4
 
Hi,

I have 4 scalar equations (all of which has a SOURCE TERM=R1 & R2), but two (ISC3 & ISC4) of the four SCALs don't have DIFFUSION or CONVECTION terms.

INDICES: ISCA=ISCAL+ISC1-1 ISCB=ISCAL+ISC2-1 ISCC=ISCAL+ISC3-1 ISCD=ISCAL+ISC4-1

(1) The following implies no diffusion terms applied to SCAL3 and SCAL 4.
:>DIFFERENCING SCHEME USER SCALAR3 'NO MATRIX' USER SCALAR4 'NO MATRIX'

(2) Then I would set the following in USRSRC under ICALL2 (for equations with no diffusion or source terms):

i)FOR (IEQN.EQ.ISCC)

SP(INODE,IPHASE)=-1*VOL(INODE) SU(INODE,IPHASE)=R1*VOL(INODE)

ii)FOR (IEQN.EQ.ISCD)

SP(INODE,IPHASE)=-1*VOL(INODE) SU(INODE,IPHASE)=R2*VOL(INODE)

My misunderstanding lies in setting SP(INODE) to -1...can some explain the need for this?

Thanks,

RK


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