Imbalance in %, Y-axis scale correct?

DBFIU · March 31, 2011, 12:48

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

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

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

March 31, 2011, 12:48	Imbalance in %, Y-axis scale correct?	#1
DBFIU New Member Dan Join Date: Mar 2011 Posts: 10 Rep Power: 15	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

April 1, 2011, 03:34	Don't stop the run	#3
bhatiadinesh Member D Join Date: Nov 2010 Posts: 50 Rep Power: 15	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

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March 31, 2011, 13:56		#2
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	I agree it's not clear, but it is a percentage. Stop the run and compare to the values printed in the .out file.

April 1, 2011, 03:35		#4
bhatiadinesh Member D Join Date: Nov 2010 Posts: 50 Rep Power: 15	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 ? )

August 31, 2013, 15:39		#5
hmasenger Senior Member hamed Join Date: Apr 2009 Posts: 148 Rep Power: 17	can you tell me how to monitor imbalance?i cant find it out?

September 1, 2013, 05:49		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	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.

September 1, 2013, 09:01		#7
hmasenger Senior Member hamed Join Date: Apr 2009 Posts: 148 Rep Power: 17	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

September 1, 2013, 18:38		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Monitor properties - plot line variable - "Residual" is one key term, and "imbalance" is another. Look under imbalance.

September 2, 2013, 13:00		#10
hmasenger Senior Member hamed Join Date: Apr 2009 Posts: 148 Rep Power: 17	i have find it in the monitor option in CFX PRE. thanx Glenn