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Poisson equation Cfx 4.4

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Old   June 3, 2004, 04:29
Default Poisson equation Cfx 4.4
  #1
Andrea
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I need model the value of a user scalar V in the fluid domain (but indipendent by the fluid).

The associated equation is similar to the heat conducting in solid.

D=gradient

D.(k*D V)=S

How can I solve this equation in Cfx 4.4?

Thanks

Andrea

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Old   June 3, 2004, 19:49
Default Re: Poisson equation Cfx 4.4
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Jeff
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Set up an additional scalar (V) and under the DIFFERENCING SCHEME set NO CONVECTION.

Set values on all walls or leave alone for zero flux.

Unfortunately, inlets are a bit trickier as they will still try to convect or diffuse a zero value into the domain. I've solved this before in USRBCS by: * Loop over each cell in the inlet patch * examine the first adjacent cell to the boundary node * set the inlet to that value This, in essence, gives a zero flux condition on the INLET patch. You may have to do this on PRESSURE patches as well if there is inflow.

Good luck, Jeff
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Old   August 17, 2004, 05:34
Default Re: Poisson equation Cfx 4.4
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windhair
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I heard it is possible to solve the NO CONVECTION problem for inlets by using BCSEXT subroutine, but I have no idea about this, because it is not included in the document. How does it works?

Thanks
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