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[snappyHexMesh] How to mesh a flow straightener

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Old   February 1, 2015, 12:30
Exclamation How to mesh a flow straightener
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Mohammad Fereshtehpour
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Dear Foamers

Hi
I need to simulate flow in a flow straightener which is shown in the picture below. To do this I used snappyHexMesh but I couldn't achieve a good results. I don't know what the problem is? As It is shown the model geometry is wrong in the pipe near the internal pipes.
If you don't mind take a look at my case. I put it in the dropBox.

https://www.dropbox.com/s/evdrcrr7ot...owStr.zip?dl=0

Best Wishes
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Old   February 1, 2015, 13:05
Default Some pictures
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Here you can see both the geometry and meshed model.
Attached Images
File Type: jpg 1.jpg (28.9 KB, 53 views)
File Type: jpg 2.jpg (34.4 KB, 44 views)
File Type: jpg 3.jpg (19.0 KB, 51 views)
File Type: jpg 4.jpg (24.7 KB, 54 views)
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Old   February 2, 2015, 14:04
Default My problem!
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As you can see in the pictures, my problem is that the wall is not modelled correctly. The wall is not defined somewhere and in those places I have inlet patch as it is shown! Why?
I think there is a problem with snapping but I don't know How to deal with?
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Old   February 2, 2015, 15:28
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Quote:
Originally Posted by MOHAMMAD67 View Post
As you can see in the pictures, my problem is that the wall is not modelled correctly. The wall is not defined somewhere and in those places I have inlet patch as it is shown! Why?
I think there is a problem with snapping but I don't know How to deal with?
Looks like you haven't refined it enough in the region where the tubes are: you may want to define a refinementRegion and increase to level so that you get at least 2 cells between then tubes and the wall.
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Old   February 2, 2015, 16:02
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Exactly that is what I mentioned in your private message. It seems that you have no refinement at all.
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Old   February 5, 2015, 02:03
Wink Problem Solved!
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Dear Marco and Tobi

Thanks for your replies. Yes, you are right! I didn't set the snappyhexmeshDict to make mesh refinement. To solve this problem, I first increased maxGlobalCells to 300000 and it started to do this!.After that I tried to separate my geometry main pipe and tubes and apply them in refinementSurfaces and refinementRegions.
But now, I have more than 1000000 cells which makes my simulation very slow!! What should I do in this manner?
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