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-   -   SIBS step size underflow (https://www.cfd-online.com/Forums/openfoam-solving/97066-sibs-step-size-underflow.html)

Abhishekd18 February 8, 2012 07:15

SIBS step size underflow
 
Hello all,

I am running dieselEngineFoam with spray. I am getting following error some time after spray injection. I checked the chemistryProperties file and tried using different solvers for ODESolver. But it didn't help. Can anyone help me on this?

Thanks.

--> FOAM FATAL ERROR:
step size underflow

From function ODES::SIBS
in file ODESolvers/SIBS/SIBS.C at line 155.

FOAM exiting

Abhishekd18 February 15, 2012 04:42

Ok. I got the reason. The solution becomes unstable after layer addition. Very high velocity (7783 m/s). Can anyone suggest how to control the solution after layer addition?

zhangyan January 13, 2017 04:44

Hi Abhishek,
Have you find a soltion later?
I met the same problem.

Abhishekd18 January 13, 2017 06:50

Quote:

Originally Posted by zhangyan (Post 633095)
Hi Abhishek,
Have you find a soltion later?
I met the same problem.

Hi Zhangyan,

Unfortunately I did not find the solution for this.

But what you could do is check the routines which map the solution onto newly added layer and see if there are any problems.

Best regards,
Abhishek

zhangyan January 13, 2017 07:04

Hi,
I find a way!
delete the faceZones pointZones and meshModifiers in the polyMesh dictionary.
then it runs well.

zhangyan March 24, 2017 02:54

Quote:

Originally Posted by zhangyan (Post 633125)
Hi,
I find a way!
delete the faceZones pointZones and meshModifiers in the polyMesh dictionary.
then it runs well.

sorry! This can't solver the problem.
The answer is: not use SIBS, or not USE ode. There are other choices.


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