SIBS step size underflow

Abhishekd18 · February 8, 2012, 06:15

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, 03:42

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, 03:44

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

Abhishekd18 · January 13, 2017, 05:50

Quote:

Originally Posted by zhangyan

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, 06:04

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

zhangyan · March 24, 2017, 01:54

Quote:

Originally Posted by zhangyan

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.

February 8, 2012, 06:15	SIBS step size underflow	#1
Abhishekd18 Member Abhishek Join Date: Dec 2010 Posts: 39 Rep Power: 15	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

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February 15, 2012, 03:42		#2
Abhishekd18 Member Abhishek Join Date: Dec 2010 Posts: 39 Rep Power: 15	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?

January 13, 2017, 03:44		#3
zhangyan Senior Member Yan Zhang Join Date: May 2014 Posts: 120 Rep Power: 11	Hi Abhishek, Have you find a soltion later? I met the same problem.

January 13, 2017, 06:04		#5
zhangyan Senior Member Yan Zhang Join Date: May 2014 Posts: 120 Rep Power: 11	Hi, I find a way! delete the faceZones pointZones and meshModifiers in the polyMesh dictionary. then it runs well.