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-   -   Imbalance in %, Y-axis scale correct? (http://www.cfd-online.com/Forums/cfx/86738-imbalance-y-axis-scale-correct.html)

DBFIU March 31, 2011 12:48

Imbalance in %, Y-axis scale correct?
 
I am running a 3D simulation in CFX using k-omega SST.

I am monitoring the run and I plotted Energy, Mass and Momentum imbalance on the same monitor chart that residuals are plotted, this chart is logarithmic Y-axis.

My question is, it says the H, U and P balances are being shown in %, if this true please confirm, because the simulation is at 1e-1 which is 0.1%, and this can easily be mistaken for 10% if it is not clear that the scale is showing actual percent values and not decimal values (for the three balance variables).

Thank you

stumpy March 31, 2011 13:56

I agree it's not clear, but it is a percentage. Stop the run and compare to the values printed in the .out file.

bhatiadinesh April 1, 2011 03:34

Don't stop the run
 
Please dont stop the run, you can just change the parameters to be plotted in the present monitor by right clicking on the plot area of the screen. Yopu can create a seperate monitor by cliking the right mouse button on the tabs above the monitros and declare a new monitor and plot any of the available parameters

-Dinesh

bhatiadinesh April 1, 2011 03:35

Also click on the respective curve and u can see the current value....btw imbalances are always shown in % but residuals are never ( % of what ? )

hmasenger August 31, 2013 15:39

can you tell me how to monitor imbalance?i cant find it out?

ghorrocks September 1, 2013 05:49

You can view the imbalances in the solver manager -Edit the data displayed on the plot to imbalances.

The imbalance is simply a % imbalance of total amount of that variable in the domain. So it checks the global conservation of the variables.

hmasenger September 1, 2013 09:01

you mean by defining a new monitor in Solver manager ?but i cant find the imbalance in the options!
there is only
Residual>max and RMS>..
and there is no imbalance .i cant find it.don't you mean that i should define an expression in cfx pre as imbalance and setup a monitor for that?or there is something in the solver manager?
pleas guide me through this.
thanks alot

ghorrocks September 1, 2013 18:38

Monitor properties - plot line variable - "Residual" is one key term, and "imbalance" is another. Look under imbalance.

hmasenger September 2, 2013 09:20

1 Attachment(s)
i don't know why there is no imbalance in the plot variable page !
it there any option in the CFX pre that must be activated to monitor imbalance which i skipped or ignored ?

hmasenger September 2, 2013 13:00

i have find it in the monitor option in CFX PRE. thanx Glenn


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