|
[Sponsors] |
December 8, 2012, 07:10 |
Problem with Convergence
|
#1 |
Member
anonymous
Join Date: Dec 2012
Posts: 33
Rep Power: 13 |
I am having a problem with my Starccm simulation in that it will not converge to a final solution. the residuals are very high are the solution never seems to reach a steady state where everything is constant it just keeps moving.
I am simulating a turbine blade and I am using the following models: gamma ReTheta K-omega Steady Turbulent 2D Coupled All Y+ treatment Ideal Gas I am hoping that there is something I can do in order to make it converge and reach a solution. I have attached some pictures so that you can tell what I mean. The solution is periodic which explains a little better the scaler plot. thanks broke_Scalar Scene 1.png broke_Residuals.png |
|
December 11, 2012, 18:08 |
|
#2 | |
New Member
Luís Ferrari
Join Date: May 2012
Posts: 1
Rep Power: 0 |
Oi, tente diminuir o fator de sobre-relaxamento, o default é 0.9, tente abaixar para 0.5, isto poderá deixar problemas de tempo em sua simulação, caso não, pode ser problema de modelo mesmo, tente colocar uma sonda e monitorar por isto.
Quote:
|
||
December 13, 2012, 03:09 |
|
#3 |
Senior Member
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 220
Rep Power: 17 |
Seems to me that the mesh is coarse. But before that try to change physics models from second order to first order. See if it gets converged or not. if yes, then change to second order after for example 2000 iterations.
__________________
Good luck Siamak |
|
December 18, 2012, 04:54 |
|
#4 |
Member
anonymous
Join Date: Dec 2012
Posts: 33
Rep Power: 13 |
I tried to change both the order from 2nd to 1st and also the couant number and also the relaxation.
The simulation converges fine if you use segregated and constant density, but if you use coupled and ideal gas it does not and gives stupid results and never reaches a steady state solution. I need to use coupled and ideal gas to match an experiment that someone else has done. |
|
December 20, 2012, 13:23 |
|
#5 |
Senior Member
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 220
Rep Power: 17 |
I think if you want to try coupled, you need to reduce more the relaxatoin factor. It will take certaily longer to converge, you need to be patient.
__________________
Good luck Siamak |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
convergence problem when use pisoFoam, LES for wind tunnel case | Forrest_Lei | OpenFOAM | 3 | July 19, 2011 06:00 |
convergence problem | commonyue | Main CFD Forum | 1 | December 1, 2009 03:54 |
Convergence of CFX field in FSI analysis | nasdak | CFX | 2 | June 29, 2009 01:17 |
3D Fluid Flow Convergence problem | Emily | FLUENT | 2 | March 21, 2007 22:18 |
Non Convergence of 3D Heat transfer cfd problem | Balraj | Main CFD Forum | 3 | December 9, 2004 00:24 |