|
[Sponsors] |
November 19, 2021, 07:50 |
Minimum Steps Criterion
|
#1 |
New Member
Adi
Join Date: Nov 2021
Posts: 4
Rep Power: 4 |
Hey,
I am investigating wing profiles with a time averaged simulation (RANS).However, depending on the angle of attack, the simulation cannot be time averaged. To be able to investigate these cases anyway, I want to average the downforce over the last 300 iterations. Since the Design Manager stops before reaching 300 itterations if the convergence is sufficient, the averaging is not possible. My ideas to solve this problem: 1. specify a minimum number of iterations. Is this possible via the Stopping Criteria -> Fixed Steps? 2. if-statement: If convergence is reached, then the downforce should not be averaged. Otherwise the downforce should be averaged. How can you implement such an expression? 3. do you have any other ideas? Thanks to all |
|
November 19, 2021, 22:46 |
|
#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,739
Rep Power: 66 |
Record a macro.
Set the number of iterations to 300 and turn off the convergence monitor as a stopping criteria. Iterate/run Turn on the convergence monitor. Iterate/run Add this macro to your design manager |
|
November 20, 2021, 06:54 |
|
#3 |
New Member
Adi
Join Date: Nov 2021
Posts: 4
Rep Power: 4 |
Unfortunately Iīm not very familiar with macros.. Isnīt there a way to implement a criteria witch says:
"Do minimum 300 iterations even tough other stopping criterias are reached"? |
|
November 20, 2021, 17:52 |
|
#4 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,739
Rep Power: 66 |
If that's all you want to do then go to your stopping criteria and change the logical rule from OR to AND
|
|
November 21, 2021, 07:42 |
|
#5 |
New Member
Adi
Join Date: Nov 2021
Posts: 4
Rep Power: 4 |
But which criterion do i need to create that i can change to AND? I tried Stopping Criterion -> New Criterion -> Fixed Steps. But this doesnt work
|
|
November 21, 2021, 21:22 |
|
#6 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,739
Rep Power: 66 |
You don't create new criteria. You need to set the existing ones to AND. Star will iterate forever unless your stopping criteria tells it to stop. I don't know your case setup to tell you which ones are stopping it before 300 iterations are done. The default criteria used in every simulation is number of iterations and residuals.
Whichever one is causing it to stop before 300 iterations you need to put to AND as well as number of iterations. |
|
Tags |
minimum steps, star ccm+ |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
A variable expressing time steps in UDF? | lcw | FLUENT | 6 | March 28, 2020 03:07 |
Get the maximum and minimum pressure in the domain(In parallel calculation) | xh110120 | Fluent UDF and Scheme Programming | 4 | October 10, 2014 08:06 |
fluid flow but temperature raises from nowhere? | mxcfd | STAR-CCM+ | 5 | September 16, 2014 05:46 |
UDF for time steps | David | FLUENT | 0 | August 14, 2007 11:54 |
transient limit is 99,999 time steps? URGENT | azmir | Siemens | 2 | April 15, 2007 22:06 |