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

StefanW · June 6, 2016, 11:25

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, 02:47

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, 04:19

Hi Akidess,

thanks for your quick reply.

That helps a lot.

Best Regards

Stefan

RodriguezFatz · June 7, 2016, 04:43

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

StefanW · June 7, 2016, 04:47

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, 05:04

Good luck

June 7, 2016, 02:47		#22
akidess Senior Member Anton Kidess Join Date: May 2009 Location: Germany Posts: 1,377 Rep Power: 30	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, 04:43		#24
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	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, 05:04		#26
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	Good luck __________________ The skeleton ran out of shampoo in the shower.

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June 6, 2016, 11:25		#21
StefanW New Member Stefan Join Date: Oct 2015 Posts: 24 Rep Power: 11	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, 04:19		#23
StefanW New Member Stefan Join Date: Oct 2015 Posts: 24 Rep Power: 11	Hi Akidess, thanks for your quick reply. That helps a lot. Best Regards Stefan

June 7, 2016, 04:47		#25
StefanW New Member Stefan Join Date: Oct 2015 Posts: 24 Rep Power: 11	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