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-   -   [Urgent] Need help for defining boundary conditions (http://www.cfd-online.com/Forums/fluent/62756-urgent-need-help-defining-boundary-conditions.html)

Jingwei March 18, 2009 23:53

[Urgent] Need help for defining boundary conditions
 
Hi all,

I'm modeling a channel flow with a winglet using Gambit, as proposed in the attached figure:
http://img27.imageshack.us/my.php?image=helpj.jpg

The boundaries that i'm currently using are:
1. Inlet: Velocity inlet
2. Outlet: Pressure outlet
3: Side walls: Periodic
4: Top wall: Symmetry
5: Bottom wall: Wall
6. Winglet: Wall

When i open the mesh file using the above-mentioned boundary conditions in FLUENT, there is a error message that says that it can't read the winglet boundary type as stated below:

==================================
materials,
interface,
domains,
zones,
default-interior
pressure_outlet
velocity_inlet
bottomwall
upperwall
Skipping zone wall (not referenced by grid).
side_walls
Skipping thread 3 of domain walls_shadow (not referenced by grid).
fluid
shell conduction zones,
Done.
==================================

Why is that so?


Also, I have a few other questions in mind:
1. As in the attached figure, the boundary at the side wall is defined as free slip. Is periodic boundary that correct boundary type to use?
2. I do not understand why the author of this paper on one hand states that the top wall is defined as a no-slip wall, in the other he states that the velocity is parabolic (i.e., Velocity_max at the top wall and Velocity=zero at the bottom wall)

Jingwei March 19, 2009 00:17

add:

I have checked the mesh in Gambit, it seems to be alright:

http://img14.imageshack.us/my.php?image=help2e.jpg

Jingwei March 19, 2009 22:01

any help pertaining to any part of the above question is welcomed!

P/S: With regards to the problem I had in the fluent as posted in #1, I think it is b/cos I run 3ddp in fluent, thus it is unable to recognise the 2D triangular structure inside.


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