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-   -   How to impose user scaler onto wall boundary (http://www.cfd-online.com/Forums/cfx/18902-how-impose-user-scaler-onto-wall-boundary.html)

Min-Hua Wang March 31, 2002 15:15

How to impose user scaler onto wall boundary
 
Hello, all:

I try to do some simulation of mass transfer though wall. I need to define a user scaler flux on the wall.I t is possible to do it by command file. Howvere, the flux may not be a constant quantity so I am thinking to use user defined subroutine (USRBCS.f).

It would be helpful if some body has the experience of similar kind.

Thanks in advance.

MHW

Astrid April 2, 2002 15:41

Re: How to impose user scaler onto wall boundary
 
- If it is constant, you can define it in the command file.

- If your scalar is a variable, you have to define it in USRBCS.f. Suppose you have a manual, check the examples on USRBCS.f on how to set variables on the boundary nodes (Chapter 10). There are also examples on how to alter scalar variables. Use GETSCA to get the correct equation number referring to your scalar (also chapter 10).

It should not be too difficult. You might need to read chapter 11 on the internal structure of CFX 4.4.

Good luck, Astrid

Min-Hua Wang April 2, 2002 17:02

Re: How to impose user scaler onto wall boundary
 
Thanks, actually, I want to impose the flux of a user scaler onto the wall boundary. I checked USRBCS.f. Any suggection ?

Thanks.

MHW

Astrid April 3, 2002 05:29

Re: How to impose user scaler onto wall boundary
 
That can be set very easy in the command file:

>>MODEL BOUNDARY CONDITIONS
>>WALL BOUNDARIES
PATCH NAME '....' (the name of your wall patch)
USER SCALAR1 FLUX ..... (a real value for scalar number 1)



You can also define a combined Neumann-Dirichlet BC:
USER SCALAR1 ABC ... ... ... (3*real value)



The manual can tell you all about it. Or check the 'CFX-4.4 Solver Summary of commands and keywords', page 16.

Good luck, Astrid

joseph April 5, 2002 08:23

Re: How to impose user scaler onto wall boundary
 
hi

Do you guys have any idea about the STEP function in CFX because it seems like you are more in to CEl.

thank for your time.

joseph


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