Laminar vs. Turbulent

Miroo · August 17, 2009, 11:58

Hi guys,

I have a small problem.
I modelled a rectangular channel (b/h=1) and
after running icoFoam the results are like analytic solution.
Now I want to try to run the same geometry with simpleFoam,
my assumption was that the result had to be the same, if the
Re=100 in both cases.

Know somebody what is my mistake?

It is easy now, but for example if in one part of the channel is
laminar flow and in the another is turbulent, ...what I have to do...???
How can I run problem like this?

Thanks

henrik · August 17, 2009, 12:18

Miroo,

yes, you need to know a-priori whether your flow is turbulent or laminar and select appropriate modeling. Transition and re-laminarisation are research topics. There are many models in the literature, but no general answer.

That's the state of the art and a general issue in CFD.

Henrik

Miroo · August 17, 2009, 18:07

Hi Henrik,

your answer was very helpfully
(und noch vor allem so schnell).
Thank you very much

Miro

August 17, 2009, 11:58	Laminar vs. Turbulent	#1
Miroo New Member Miro Join Date: Aug 2009 Posts: 14 Rep Power: 16	Hi guys, I have a small problem. I modelled a rectangular channel (b/h=1) and after running icoFoam the results are like analytic solution. Now I want to try to run the same geometry with simpleFoam, my assumption was that the result had to be the same, if the Re=100 in both cases. Know somebody what is my mistake? It is easy now, but for example if in one part of the channel is laminar flow and in the another is turbulent, ...what I have to do...??? How can I run problem like this? Thanks

August 17, 2009, 18:07	Thank you	#3
Miroo New Member Miro Join Date: Aug 2009 Posts: 14 Rep Power: 16	Hi Henrik, your answer was very helpfully (und noch vor allem so schnell). Thank you very much Miro Last edited by Miroo; August 17, 2009 at 18:30.

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August 17, 2009, 12:18		#2
henrik Senior Member Henrik Rusche Join Date: Mar 2009 Location: Wernigerode, Sachsen-Anhalt, Germany Posts: 281 Rep Power: 18	Miroo, yes, you need to know a-priori whether your flow is turbulent or laminar and select appropriate modeling. Transition and re-laminarisation are research topics. There are many models in the literature, but no general answer. That's the state of the art and a general issue in CFD. Henrik