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Waleedooo March 8, 2013 20:24

mesh generation for wind tunnel
1 Attachment(s)
Dear friends, I'm asking all of you to help me in this problem

first i'm going to represent the wind tunnel in fluent so i have to prepare the model first and i want to use a size function with a boundary layer to make the mesh too smooth over the building faces and going with a good grading until reaching the tunnel walls and become coarse, and my questions are:

1- when defining the size function I'm choosing the building faces as sources and the domain flow or the air domain as the attachment, so is that correct???

2- when defining the boundary layer I'm choosing the 5 faces of my building as the attachment but when I'm checking the shape of the layer i found it coming over the tunnel bottom only or the grading coming over the surface of the tunnel bottom only, so how i can solve this problem to see the grading coming around my building and starting from the building faces smooth and going coarse away from the building faces?

the attached file is for my model, so could any body helping me because this is too much urgent for me in my study, thank you very much my friend and looking for your cooperation, bye bye

-mAx- March 11, 2013 07:17

1- yes
2- I cannot open your zip file

Waleedooo March 11, 2013 16:48

My Friend I think it a *rar file not a zip file so please try to open it with winrar, thank you very much for your cooperation,


-mAx- March 12, 2013 08:29

before applying size function, set your BL on your walls.

Waleedooo March 12, 2013 16:21

I tried to do that many times but its not working, could you explain in a steps the setting boundary layers and the size function, thank you

-mAx- March 13, 2013 03:00

-import your .sat file.
-go to BL panel, switch to faces (Attachmane), and select faces on which you want to apply BL.
-Enable internal continuity and wedge corner shape
-set first row and if desire increase Rows number (and/or growth factor)

-Then go to Size Function, in Source switch to surfaces and select the surfaces which will be fine meshed, and choose attachmen (in your case your volume). Start size is your minimal celll size, then growth rate (1.2 for example, and your max size.

Waleedooo March 13, 2013 11:55

Thank you very much my friend, I'll try it and I'll tell you whats happen with me, thank you very much

Waleedooo March 17, 2013 19:11

Dear Friend,

I did exactly what you said and I generate the mesh and its the same as what I did before, the mesh coming smooth on the tunnel bottom only and the faces of the building but for the volume coming coarse and I'm still confused because I'm feeling that the transition from coarse volume cells to the smooth faces cells will not give an accurate results, I did the following
1- creating the B.L. and I choose the 5 faces of the building and first/last aspect was 3 and the number of rows =12 the sources as I said 5 faces of the internal building then ok
2- the second step is defining the size function and its starting from faces and the attachment is the volume
3- meshing using tetrahedral/ t-grid

Could you tell me if I did somthing wrong or could you try it, thank you


-mAx- March 18, 2013 04:15

display picture of your mesh: go to examine mesh, and choose "cut".
Display a cut in the middle, to see what sounds weird according to you

Waleedooo March 18, 2013 11:24

2 Attachment(s)
my friend please check the atachements here, you will find 2 images the first one is from outside the cube and not represent the real mesh but when I did the cut as you said its coming different, oh my God is the internal cut reprenst the real mesh or not, I spent more that a month now with this issue and you guided me to the internal cut plane, so is what I did with this mesh correct or not

thank you very much for the advices and waiting for your reply, thanks again

-mAx- March 19, 2013 03:08

yes second is your real mesh (you see what's append inside your domain)
on your first picture you only see boundary mesh
From second picture you can see the size function: mesh is fine on your cube and is growing

Waleedooo March 19, 2013 19:36

Thank you
Dear friend ,

I appreciate what you did with me, Thank you Very much


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