[Other] No layers added on the inclined tube

vinezio · August 30, 2012, 12:53

Hi All,
I'm using OpenFOAM 2.0.0 and i would to create a model with SnappyHexMesh. In the following picture is explained my problem. Why it happen that? How can I do to add the layers on the bent tube? I need help!!

Regards,
vinezio

simpomann · September 27, 2012, 05:01

Hi,

I experience a similiar problem in a complex pipe network. So far, I could only properly add layers using a refinement box around the geometry and refine it on a high level. Some straight elements get layers without the refinement as well, but I run into problems where the pipe bends, just like you.
Setting the size to absolute (relativeSize false) was also my guess, but didn't solve it.

Did you find a solution?

Greetings,
Simon

vinezio · September 27, 2012, 14:02

Hi Simon,

thanks for your suggestions and just 2 days ago i've found alternative solution. I've drastically reduced nSmoothPatch and nRelaxIter iteration and i've set in the mesh quality minVol at 1e-250. In this way i've reached 100% layers distribution but when I try to run with simpleFoam solver the solution not converge very well! I just open a new post for that -- Problem in sHM.
To help you, I post sHM's file. Let me know how it goes.

vinezio

simpomann · September 28, 2012, 11:02

Hi vinezio,

I tried with your settings, but they don't lead to any improvement. Thanks for providing them! The funny thing is that the same case is meshing perfectly with OF 1.6 (tried today at work in university). So actually now I think about meshing at work and solving at home, what is kind of disappointing as my home version is 2.1.0 and should work better, especially concerning this issue. Or I will try the sHM-Dict from 1.6 under 2.1., but I am afraid it will ask me to include the new quality settings (and disabling all of them yesterday didn't lead me anywhere).

This is driving me crazy. I spend 12 hours trying to mesh it with OF 2.1.0 and no success, while it took me 20 minutes with OF 1.6 to find a suitable absolute layer size and no problems (with a 12mm pipe in a 100mm square blockmesh with bendings in 3 directions, diffusors and everything).

If I ever find out what is behind this I will post it here.

Tobi · October 26, 2012, 03:27

Hi,

did you compare your quality settings of both sHMDicts ?
I think in your 1.6 your mesh quality parameters are lower than in OF2.1.x.
If you disable everything you ll get layers all over the geometry!

simpomann · October 26, 2012, 05:12

Hey,

Thanks you mention it, but my 2.1 SHM-Dictionary is actually my 1.6 SHM-Dictionary with the new settings added (and disabled).

I found some "work around" in the mean time by chosing a smaller blockMesh and decided that I can live with the additional cells.

Best regards,

Simon

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September 27, 2012, 05:01		#2
simpomann Member Simon Arne Join Date: May 2012 Posts: 42 Rep Power: 13	Hi, I experience a similiar problem in a complex pipe network. So far, I could only properly add layers using a refinement box around the geometry and refine it on a high level. Some straight elements get layers without the refinement as well, but I run into problems where the pipe bends, just like you. Setting the size to absolute (relativeSize false) was also my guess, but didn't solve it. Did you find a solution? Greetings, Simon

September 28, 2012, 11:02		#4
simpomann Member Simon Arne Join Date: May 2012 Posts: 42 Rep Power: 13	Hi vinezio, I tried with your settings, but they don't lead to any improvement. Thanks for providing them! The funny thing is that the same case is meshing perfectly with OF 1.6 (tried today at work in university). So actually now I think about meshing at work and solving at home, what is kind of disappointing as my home version is 2.1.0 and should work better, especially concerning this issue. Or I will try the sHM-Dict from 1.6 under 2.1., but I am afraid it will ask me to include the new quality settings (and disabling all of them yesterday didn't lead me anywhere). This is driving me crazy. I spend 12 hours trying to mesh it with OF 2.1.0 and no success, while it took me 20 minutes with OF 1.6 to find a suitable absolute layer size and no problems (with a 12mm pipe in a 100mm square blockmesh with bendings in 3 directions, diffusors and everything). If I ever find out what is behind this I will post it here.

October 26, 2012, 03:27		#5
Tobi Super Moderator Tobias Holzmann Join Date: Oct 2010 Location: Tussenhausen Posts: 2,708 Blog Entries: 6 Rep Power: 51	Hi, did you compare your quality settings of both sHMDicts ? I think in your 1.6 your mesh quality parameters are lower than in OF2.1.x. If you disable everything you ll get layers all over the geometry!

October 26, 2012, 05:12		#6
simpomann Member Simon Arne Join Date: May 2012 Posts: 42 Rep Power: 13	Hey, Thanks you mention it, but my 2.1 SHM-Dictionary is actually my 1.6 SHM-Dictionary with the new settings added (and disabled). I found some "work around" in the mean time by chosing a smaller blockMesh and decided that I can live with the additional cells. Best regards, Simon