CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

SlidingInteface adjustTimeStep and Courant problems

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 25, 2008, 12:52
Default Hi everybody, I just have a
  #1
Senior Member
 
Frank Bos
Join Date: Mar 2009
Location: The Netherlands
Posts: 338
Rep Power: 9
lr103476 is on a distinguished road
Hi everybody,

I just have a 3D spherical sliding interface around a rotating object. The case is working using moveDynamicMesh. All schemes are default and boundary conditions are just symmetric and 1 inflow and 1 outflow, so very basic. Reynolds number is about 200....

The problem is: in controlDict I've put maxCo to 0.5, but icoDyMFoam doesn't seem to care. While iterating the timestep reduces such that meanCo is about 1e-5 and maxCo about 1e-3......

Has anyone observed similar problems, could it be related to boundary conditions or to the choice of schemes?

Regards, Frank
__________________
Frank Bos
lr103476 is offline   Reply With Quote

Old   February 25, 2008, 13:31
Default Hi Frank Good Evening I
  #2
Senior Member
 
Join Date: Mar 2009
Posts: 248
Rep Power: 9
jaswi is on a distinguished road
Hi Frank

Good Evening

I have been facing the similar problem with my sliding interface.

The first guess is that the timeStep, meanCo amd maxCo are mesh size dependent. Haven't tried the same setup with a coarser mesh so cannot establish the dependence.

If you are using blockMeshDict and can coarsen you mesh quickly then keep the same solver settings as now and try different mesh resolutions.

Please let me know if you figure out the dependence.

With Best Regards
Jaswinder
jaswi is offline   Reply With Quote

Old   February 25, 2008, 17:22
Default Hi Jaswinder! I don't use b
  #3
Senior Member
 
Frank Bos
Join Date: Mar 2009
Location: The Netherlands
Posts: 338
Rep Power: 9
lr103476 is on a distinguished road
Hi Jaswinder!

I don't use blockMesh, and I am aware that a moving mesh with smaller cells leads to smaller timesteps and larger Courant numbers.....

The problem is that I define maxCo in controlDict and the solver doesn't even come close to that value. It doesn't diverge either, the adjustable timestep just becomes very very small and the maxCo far below the desired value in controlDict.

Very strange, anyone any ideas?

Frank
__________________
Frank Bos
lr103476 is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
AdjustTimeStep question danvica OpenFOAM Running, Solving & CFD 1 January 11, 2008 06:32
courant no Cfdworker Phoenics 5 October 13, 2006 08:29
courant no. Cfdworker CD-adapco 5 February 12, 2006 02:04
On the Courant number . raintung FLUENT 3 May 7, 2003 06:03
Courant Number Parshant Dhand FLUENT 1 April 29, 2003 20:39


All times are GMT -4. The time now is 10:12.