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-   -   using turbulence and laminar model in the same time (http://www.cfd-online.com/Forums/fluent/84715-using-turbulence-laminar-model-same-time.html)

hamid1 February 7, 2011 09:46

using turbulence and laminar model in the same time
 
Hi Guys

i am simulating a domain in which one part feels low Reynolds and laminar regime while the other part use high enough Reynolds for considering turbulence regime.
is it feasible in fluent to simulate this domain using both laminar and turbulence model in the related region in the domain in the same time?

your hints will help me lot
Thanks

DoHander February 7, 2011 09:59

Yes, you can mix in the same simulation turbulent and laminar zones, you can do this manually from the boundary conditions panel.

Have you considered to use one of the transition models from Fluent 12 and 13 ?

Do

hamid1 February 7, 2011 10:14

Hi Do, thanks for response
Would you explain a little bit more how can I do that through boundary condition? Is it only featured in fluent 12 cause I am currently using old version of fluent,

DoHander February 7, 2011 10:28

You have two options:

1. Manually split the domain in laminar and turbulent regions (this is available in older Fluent version too). This can be done from the BC panel if you split the mesh in regions in Gambit for example.

2. Use a transition model, this is available starting from Fluent 12 ...

hamid1 February 7, 2011 10:58

Thanks for reply,
I can split the domain in gambit, I think then there would be two domain which are separated via an interface, now what is the role of B.C.? How can I apply laminar in one part and turbulence in the other one, cause in fluent u have the only option that choos either of laminar or turbulence through DEFINEMODEL VISCOUSE

hamid1 February 7, 2011 17:33

Hi Do, or anybody who can help me;

Could you let me know how you adjust the menu in fluent for capturing laminar in one zone and turbulence in other one?
thanks

Amir February 8, 2011 04:55

Hi hamid,
as Do said, if you want to specify a zone in which laminar flow is solved, you can use BC panel as follow:
In fluid zone you can tick the laminar zone option... .

bishop_house February 8, 2011 12:07

Hello, I am using the 6.2 version of fluent, but I can't find the laminar zone option, where it should be?

Thanks for the help

DoHander February 8, 2011 12:21

It is on the boundary condition panel.

Do

hamid1 February 9, 2011 17:20

I am asking that the people who are intending to help upload comment not the people who intend to business, this forum is not for that, that person knows who I am talking about...

DoHander February 9, 2011 22:48

A possible solution
 
2 Attachment(s)
Here is a possible solution to define laminar/turbulent regions using Gambit and Fluent:

1. Split the mesh in Gambit in a turbulent and laminar region.
2. Give names to these two regions (this will ease your work later in Fluent see the attached laminar_turbulent.png image). At left I've defined a laminar region and at right a turbulent region.
3. Define the boundary conditions.
4. Export the mesh.
5. Load the mesh in Fluent.
6. In the Define panel chose Viscous and one turbulence model.
7. From the Boundary Condition panel select the laminar region and check the "laminar region" on the panel (see my second attached picture).

Now, Fluent will cancel the turbulence model in the region defined as laminar.

Hope this will help,

Do
Attachment 6435

DoHander February 9, 2011 22:51

If there is enough interest for the above procedure I can write a step by step blog entry; however the procedure is a bit outdated since starting from Fluent 12 you can use directly a transition model.

langelos November 30, 2011 04:44

hello Do!!!
 
i'm interested to write all the procedure for separeting the field in laminar and turbolent part.


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