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Old   February 8, 2005, 07:41
Default USRBCS
  #1
RK
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Hi:

I want to do appy this at inlet:

(1) IF KSTEP.EQ.0 THEN

T(inode,iphase)=X1.

BUT

(2) IF KSTEP.GT.0 THEN

T(inode,iphase)=X2.

If I only write (2) in USRBCS and have (1) in command file (fc) would this work...or do I have to write both statements in USRBCS?

I hope this makes sense.

Thanks in adcance.

RK
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Old   February 13, 2005, 01:20
Default Re: USRBCS
  #2
Jeff
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Robin,

USRBCS gets called "after" everything is set in the command file, to allow you to overwrite what's been set. You can put the second case in USRBCS to apply only after KSTEP > 0. Please note however that boundary conditions are set using the array

VARBCS(IT,INODE,IPHASE) = value

Where IT is the equation number for temperature, returned from:

CALL GETVAR('USRBCS','T ',IT).

Also, don't forget to set IUBCSF = 3 so that USRBCS gets called for changing iteration and/or time step. Otherwise, USRBCS will assume a static boundary condition and only call the routine once.

Jeff
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Old   February 23, 2005, 05:10
Default Re: USRBCS
  #3
Franklin
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Hi, Following up on Robins request, I guess the difficult part is the wall boundary conditions. I have been trying to implement a stress model at the boundary for sometime now FOR TWO-PHASE TURBULENT FLOWS. Basically, this model has a gradient of velocity in it. However, by using SETWRK AND GRADV routines, I get floating invalid error.

I noticed in the documentation the following under the discussion of GRADV: "Note that, in turbulent flows, the gradient at the wall of the velocity components is stored at the cell centre adjacent to the wall."

Can someone help with this? Thanks in advance. Franklin.
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