|
[Sponsors] | |||||
convergence criteria by lift and drag coefficent |
![]() |
|
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
|
|
|
#1 |
|
New Member
Join Date: Feb 2011
Posts: 2
Rep Power: 0 ![]() |
Hello,
I have modelled a flow over an airfoil in cfx which works fine so far. Futhermore i have created monitorpoints for lift- and drag-coefficent. What i want to do now is to set a interrupt control condition in cfx pre so that the actual value of the coefficent is compared to the one ten iterations before. If the difference is under a defined limit (let's say 0.1%) the simulation should be stoped. My problem is that I don't know the CEL-Syntax to get a value at a certain iteration. Maybe somebody knows how to program that. Thanks |
|
|
|
|
|
|
|
|
#2 |
|
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 18,011
Rep Power: 146 ![]() ![]() ![]() ![]() |
This cannot be done easily in CEL.
You will probably find a residual convergence tolerance to correspond to your coefficient convergence. Then you could just use a simple residual convergence tolerance. If you insist on using your coefficients to judge convergence then I would have a cron job running in the background (ie outside of CFX) which monitors the monitor point output files and when it senses convergence it runs the cfx5stop command. |
|
|
|
|
|
|
|
|
#3 |
|
New Member
Join Date: Feb 2011
Posts: 2
Rep Power: 0 ![]() |
Thanks for the reply. I think I'll go with the normal residuals so far. I had a phoncall with the CFX-Support yesterday and they told me the same. Maybe when I have more time I'll try to pragramm some tool to monitor the coeffiecents and stop the solver run.
|
|
|
|
|
|
|
|
|
#4 |
|
Senior Member
Join Date: Mar 2009
Location: Europe
Posts: 169
Rep Power: 18 ![]() |
The service send me an user fortran example, which stores older values, some time ago. I am not permitted to distribute further, however you may get it if you ask.
__________________
- - - - - ------------------------------------------------------------------------ Please do not forget: I am not paid for answering your questions. Thousands of issues can cause a division by zero. Please do not capture a thread, with the argument: "I have the same issue ...." |
|
|
|
|
|
![]() |
| Tags |
| cel expression, coefficient, convergence, drag, lift |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Lift and Drag ??? | Yogibear | STAR-CCM+ | 5 | November 2, 2023 18:14 |
| Lift and Drag Monitor Point Values Converging to Zero | Josh | CFX | 24 | May 9, 2011 11:38 |
| Correct lift but wrong pressure drag - possible? | zx | Main CFD Forum | 4 | July 28, 2007 00:38 |
| drag and lift coefficient | Noé | Siemens | 5 | July 13, 2004 11:21 |
| Fluid mechanics / drag & lift | Jamcam | Main CFD Forum | 0 | October 31, 2002 05:39 |