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-   -   Define scalar wall boundary by USRBCS? (http://www.cfd-online.com/Forums/cfx/20020-define-scalar-wall-boundary-usrbcs.html)

 windhair November 26, 2003 07:14

Define scalar wall boundary by USRBCS?

How can I define a user scalar boundary condition on the wall using USRBCS? I'm not totally understand the meaning of A, B and C. Can someone kindly do me a favour.

Thx.

 Dougal McQueen November 26, 2003 08:31

Re: Define scalar wall boundary by USRBCS?

Hi, I'm just been through the same problem myself. In my opinion it is a rather wierd way of working. As you will see in the code the equation is formed: AT + BQ = C, so if you want the scalar quantity at the wall to equal X, set A=1, B=0, C=X. If you want the scalar flux equal to Y set A = 0, B = 1, C=Y. You get the idea. You need to specify the scalar poointer as thus: e.g. CALL GETVAR('USRBCS','SCAL ',IVSCAL) CALL GETSCA('SCALAR NAME',ITSCAL,CWORK) ISCAL = IVSCAL - 1 + ITSCAL then in a loop: VARBCS(ISCAL,IPHS,INODE) = #Value

I hope that this helps a little.

 windhair November 26, 2003 09:00

Re: Define scalar wall boundary by USRBCS?

Thanks, I got it.

For my problem, it will look like

DO I = 1, NPT INODE = IPT(I) A(ISCAL, IPHASE, INODE) = 1.0 B(ISCAL, IPHASE, INODE) = 0.0 C(ISCAL, IPHASE, INODE) = 0.3 ENDDO

this will define a value scalar on boundary. Right?

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