why pimple foam used under relaxation in all iteration of pimple Loop ?

StefanW · June 6, 2016, 10:25

Hey Guys,

could somebody please explain me the difference according the relaxationFactors using:

equations
{
"(U|k|omega)" 0.3;
}

or using:
equations
{
k 0.3;
omega 0.3;
U 0.3;
}

Are the one solved implicit and the others explicit ??

But I thought equations are always solved implicit?

And what is the advantage ? Could you please help me out?

Thanks a lot

akidess · June 7, 2016, 01:47

The advantage is that you can tune all three equations with one change instead of three. It's pure convinience. You'll see that notation in other places too.

StefanW · June 7, 2016, 03:19

Hi Akidess,

thanks for your quick reply.

That helps a lot.

Best Regards

Stefan

RodriguezFatz · June 7, 2016, 03:43

Hey Stefan, but normally you don't need such low under-relaxation factors for the turbulent paramters.

StefanW · June 7, 2016, 03:47

Hey Rodriguez,

thanks for your comment.

I know they are a little bit rough. So I will try step by step to enlarge them.
Sadly I got a really dynamic problem which colapses without underrelaxation.

Lets see how far i can bring them

Regards
Stefan

RodriguezFatz · June 7, 2016, 04:04

Good luck

June 7, 2016, 01:47		#22
akidess Senior Member Anton Kidess Join Date: May 2009 Location: Germany Posts: 1,377 Rep Power: 29	The advantage is that you can tune all three equations with one change instead of three. It's pure convinience. You'll see that notation in other places too. __________________ On twitter @akidTwit Spend as much time formulating your questions as you expect people to spend on their answer.

June 7, 2016, 03:43		#24
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 26	Hey Stefan, but normally you don't need such low under-relaxation factors for the turbulent paramters. __________________ The skeleton ran out of shampoo in the shower.

June 7, 2016, 04:04		#26
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 26	Good luck __________________ The skeleton ran out of shampoo in the shower.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[blockMesh] error message with modeling a cube with a hold at the center	hsingtzu	OpenFOAM Meshing & Mesh Conversion	2	March 14, 2012 09:56
[blockMesh] BlockMesh FOAM warning	gaottino	OpenFOAM Meshing & Mesh Conversion	7	July 19, 2010 14:11
NACA0012 geometry/design software needed	Franny	Main CFD Forum	13	July 7, 2007 15:57
[blockMesh] Axisymmetrical mesh	Rasmus Gjesing (Gjesing)	OpenFOAM Meshing & Mesh Conversion	10	April 2, 2007 14:00
[Gmsh] Import gmsh msh to Foam	adorean	OpenFOAM Meshing & Mesh Conversion	24	April 27, 2005 08:19

June 6, 2016, 10:25		#21
StefanW New Member Stefan Join Date: Oct 2015 Posts: 24 Rep Power: 10	Hey Guys, could somebody please explain me the difference according the relaxationFactors using: equations { "(U\|k\|omega)" 0.3; } or using: equations { k 0.3; omega 0.3; U 0.3; } Are the one solved implicit and the others explicit ?? But I thought equations are always solved implicit? And what is the advantage ? Could you please help me out? Thanks a lot

June 7, 2016, 03:19		#23
StefanW New Member Stefan Join Date: Oct 2015 Posts: 24 Rep Power: 10	Hi Akidess, thanks for your quick reply. That helps a lot. Best Regards Stefan

June 7, 2016, 03:47		#25
StefanW New Member Stefan Join Date: Oct 2015 Posts: 24 Rep Power: 10	Hey Rodriguez, thanks for your comment. I know they are a little bit rough. So I will try step by step to enlarge them. Sadly I got a really dynamic problem which colapses without underrelaxation. Lets see how far i can bring them Regards Stefan