extracting residuals

  • 42 Views
  • Last Post 15 March 2019
  • Topic Is Solved
FrankR posted this 14 March 2019

Dear Community,

 

I have log files (created in the GUI) to extract residuals from a FLUENT simulation.

But graphics from these scripts are generated only in the immediate aftermath of a simulation, when everything is still present on FLUENT's mind. Once FLUENT is closed and opened again, the residuals are not plotted, though I do get from the TUI command
(residual-history "continuity")
a list of data in the Console. If I open the dat file from the last time step of the simulation, all residuals from all time steps and all iterations are printed to the console. But a graphical output of the residuals is not available, only the grid is shown on the screen.

 

The User's Guide states:

29.15.1.11. Postprocessing Residual Values
If you read case and data files into ANSYS Fluent, you will need to perform at least one iteration before the residual values are available for postprocessing.


In the TUI I get:
/plot> residuals
 Error: No iterations performed
 

 
Questions:
Did I detect an inconsistency in the manual ?
Why do I need to perform an iteration to extract graphical data from a completed simulation, even though text output is available ?
How can I avoid overwriting data from that simulation by executing an additional iteration ? I do not want to interfer with a completed simulation.
Is it critical where to insert that additional iteration ? Should I open the last timestep n of the simulation and put 'number of time steps' = 1 in the Task Page, to end up with n+1 time steps ?

 
I searched this forum here, in vain, with the keyword 'residuals'.

 
Could someone please shed light ? 

 


I use the FLUENT "Academic Student Release" 19.2 on a Windows-PC in stand-alone mode (not using Workbench).

Thank you for your advice,

FrankR

Order By: Standard | Newest | Votes
rwoolhou posted this 14 March 2019

If you've tried to access data that's not present until you've done an iteration the TUI warning is probably correct.  If you just want to do an iteration, type  it 1  into the TUI.  This will carry out one iteration, and not advance the timestep (if it's transient). 

  • Liked by
  • FrankR
FrankR posted this 15 March 2019

Dear rwoolhou

thank you

Sincerely

FrankR

Close