CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

simpleFoam divergence due to hardware/compilation?

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   May 16, 2018, 16:17
Default simpleFoam divergence due to hardware/compilation?
Senior Member
Join Date: Jul 2013
Posts: 117
Rep Power: 10
wildfire230 is on a distinguished road
Hi all,

I have a case I am working with using simpleFoam with OpenFOAM 5.0. The problem has a lot of interesting features including variable viscosity and coupled transport equations. I have the same version of OpenFOAM compiled on my Ubuntu 16.04 laptop as well as on the Titan supercomputer at Oak Ridge National Lab. Basically on my laptop, the code seems to execute perfectly with nice convergence, but on Titan, after about 30 seconds of simulation time, simpleFoam suddenly diverges.

I have tried debugging every possible thing I can think of, but when I finally just ran an identical case on two different machines and found divergence on one (after running smoothly for a while), and no divergence on the other machine, I became very concerned. To be honest I do not know enough details about hardware/compilations to debug this problem.

Does anyone have any idea what could be going wrong???

wildfire230 is offline   Reply With Quote

Old   May 17, 2018, 00:29
Senior Member
piu58's Avatar
Uwe Pilz
Join Date: Feb 2017
Location: Leipzig, Germany
Posts: 681
Rep Power: 11
piu58 is on a distinguished road
Assuming that there is no failure in the large machine, one has to ask What is different? I think that the floating point operating units may be different and with it the internal representation of floating point numbers. A setup at the limits of stability may crashes with some less digits in floating point representation.
Uwe Pilz
Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950)
piu58 is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Floating Point Exception Error nyox FLUENT 11 November 30, 2018 12:31
Two Phase Flow In Vertical Pipe stonepreston FLUENT 2 October 31, 2017 08:35
kklOmega SimpleFoam divergence, kt kl omega NRA OpenFOAM Running, Solving & CFD 9 February 18, 2017 08:54
PimpleFoam Womersley type Flow: Divergence due to underdetermined cells 90nash OpenFOAM Running, Solving & CFD 4 July 1, 2014 01:14
solution divergence due to turbulence Haider FLUENT 1 October 18, 2006 07:27

All times are GMT -4. The time now is 15:25.