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[ICEM] NEED HELP!! Uncovered faces

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Old   November 10, 2018, 05:02
Default NEED HELP!! Uncovered faces
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Nikhil
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Hi everyone! I am having trouble in getting rid of uncovered faces in between the two blocks(please see the link for the image below).

The link for the image is :

https://drive.google.com/open?id=126...56BRc8YhWSVQxG
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Old   November 11, 2018, 12:34
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Daniel
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This sounds like a problem I just had: Unwanted "Primitive 2D" surfaces shown in CFx-PRE


In my case I merged the "double" nodes of the mesh at the interface between these "uncovered volumes".
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Old   November 11, 2018, 17:28
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Thanks for the reply! We merged the vertices earlier and that's how we got the uncovered faces. I read your thread and I was wondering how did you delete the mesh surfaces
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Old   November 11, 2018, 20:14
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Quote:
Originally Posted by nikhil07071990 View Post
Thanks for the reply! We merged the vertices earlier and that's how we got the uncovered faces. I read your thread and I was wondering how did you delete the mesh surfaces

Edit Mesh -> Delete elements


If you hide the mesh volumes then you should be only able to select mesh surfaces.


You're also working on AE4202, aren't you? It's 2:15 right now and there's no end in sight...
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Old   November 12, 2018, 03:36
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Haha ya man. And now, we are struggling with reducing the y+ value. I wish you good luck .

I'll try out what you just wrote
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Old   November 12, 2018, 07:33
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I managed to run the simulation on my y+<1 mesh this morning at 4:00, so I might be able to help if you have some minor issue. You might get an error message about Hexahedral elements being degenerated, in that case I can definitely help.
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Old   November 12, 2018, 07:56
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Nice. Good for you! Well, I don't have that error but I just can't seem to bring y+ below 2.5. I use this -- https://www.computationalfluiddynami...t-cell-height/ -- to calculate the max height of the cell.
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Old   November 12, 2018, 07:59
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Why not? If you use all the correct options there you should get a cell height of something to the power of -6. Is it just showing NaN for you?
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Old   November 12, 2018, 08:03
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I am using a value of 9.23e-7. What did you use?
I put velocity as 250.047 m/s
length - 1m
Density - 1.21 kg/m3
Viscosity - 18.03e-6
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Old   November 12, 2018, 08:31
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I just realised where I am going wrong but I dont know how to fix it. Y+ plus is less than one everywhere but at the rear of the airfoil. It seems as if the rear part of the airfoil is in another block. Any idea how to fix that?
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Old   November 12, 2018, 08:49
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Quote:
Originally Posted by nikhil07071990 View Post
I am using a value of 9.23e-7. What did you use?
I put velocity as 250.047 m/s
length - 1m
Density - 1.21 kg/m3
Viscosity - 18.03e-6

That density is incorrect. Apply the ideal gas law to the given boundary conditions.
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Old   November 12, 2018, 08:51
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Quote:
Originally Posted by nikhil07071990 View Post
I just realised where I am going wrong but I dont know how to fix it. Y+ plus is less than one everywhere but at the rear of the airfoil. It seems as if the rear part of the airfoil is in another block. Any idea how to fix that?

I set the first cell height at the wall to the required value (for y+=1) everywhere on the airfoil. Shouldn't that mean that I have a y+ of 1 everywhere? Or do I need to take into account the "local" density, viscosity and velocity? I didn't think about this before tbh.
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Old   November 12, 2018, 09:58
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Thanks for your help! We solved the problem. I think you have to consider the local variables/parameters. But as long as you get y+ less than i guess you dont need to look into it
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Old   November 12, 2018, 12:44
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Which model did you choose for anisotropic turbulence and which advection scheme?
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Old   November 12, 2018, 14:50
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Quote:
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Which model did you choose for anisotropic turbulence and which advection scheme?

I'll send you a PM.
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