|June 9, 2009, 11:45||
stability and number of processors ??
Join Date: Mar 2009
Location: Stockholm, Sweden
Posts: 15Rep Power: 9
is it possible that running a case in parallel affects the stability? I know it sound strange, but I tested exactly the same case with different processors and it looks like the higher the number of processors the smaller the Co number required in order to assure stability. I do not think it is a problem of how openFoam is installed in the cluster otherwise the simulation would not run at all.
It is a bit puzzling, did anybody experience something similar?
The test I am talking about is a Euler-Euler (solved with twoPhaseEulerFoam) gas-liquid 2D vertical channel 50mmx3mm (500x30 cells). The gas is injected from one of the two longer walls, top and bottom are inlet and outlets. I decomposed the channel for parallel calculation only along the longer dimension (y). I tried 1, 8 and 24 processors runs. The Co number in order to assure stability was respectively 1.0, 0.5, 0.1.
I know that some solvers does not scale very well with grids of less that 10,000 cells, but the issue I do not understand concerns the stability rather than the performance.
Thanks in advance
|Thread||Thread Starter||Forum||Replies||Last Post|
|about Courant number||Daniel||Main CFD Forum||4||February 9, 2008 02:58|
|Reynold's number and incompressible flow||Neil||Main CFD Forum||3||October 24, 2006 08:11|
|stability analysis||dusky.he||Main CFD Forum||2||March 24, 2006 00:49|
|stability at high Mach number flow||mike||Main CFD Forum||0||July 2, 2004 18:41|
|A question about Peclet number||Zhong Lei||Main CFD Forum||8||March 12, 1999 09:26|