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-   -   problem in using of additional variable in wall velocity (http://www.cfd-online.com/Forums/cfx/104714-problem-using-additional-variable-wall-velocity.html)

adsladsl July 13, 2012 11:09

problem in using of additional variable in wall velocity
 
Hi,everyone!
I try to use of additional variable (velo_x) in wall velocity, but i meet this solving error message:

Error processing expression 'global frame vector associated with Wall U'.
The expression is invalid because:
velo is not available for use in this term

Error processing expression(s):
Wall U = velo_x
Wall V = 0 [m s^-1]
Wall W = 0 [m s^-1]
+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| C:\Program Files\ANSYS Inc\v140\CFX\bin\winnt-amd64\ccl2flow.exe |
| was interrupted by signal QUIT (3) |
+--------------------------------------------------------------------+


This run of the ANSYS CFX Solver has finished.

How can i solve this error?

flotus1 July 13, 2012 11:12

what is the expression for "velo_x"? or is it just a constant value?

adsladsl July 13, 2012 11:17

hi,
velo_x = ctstep [m s^-1]

flotus1 July 13, 2012 11:24

ctstep is the current time step, am I right? So you want to ramp the wall velocity.
Not all variables can be used for solver input in cfx.
Try the same referencing to the flow-time.

adsladsl July 13, 2012 11:48

thanks,
when i use expression in the wall velocity, not exist this error.
i want to define wall velocity with additional variable, how solve this problem?
how can i convert the value in additional variable to expression or constant value for use the wall velocity?

flotus1 July 13, 2012 11:56

I don't know.

But if the wall velocity works when you apply an expression to it, why don't you do it this way?

adsladsl July 13, 2012 12:24

I use of additional variable for save value in last iteration with “Update Loop = TRANS_LOOP”, and then i use this value in new iteration. So i am forced using of additional variable.


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