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[GAMBIT] 2D turbulent flow in axisymmetric sudden expansion |
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December 22, 2014, 09:06 |
2D turbulent flow in axisymmetric sudden expansion
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#1 |
New Member
cecè
Join Date: Dec 2014
Posts: 3
Rep Power: 11 |
hi guys,
I am a student in mechanical engineering . I'm working on a project for the cfd examination and I can not find a solution to the problem . in particular I have to study the 2D turbulent flow of water in a pipe with a sudden expansion using the wall function approach and the near wall modeling approach and compare the results . Could someone explain how to create the mesh in gambit to obtain a valid results from the simulation ??? in particular I would like to know how to get the correct value of y + for the two different approaches . If you have any links to be attached that explains this i am very grateful . have a nice evening |
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December 23, 2014, 01:06 |
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#2 |
Super Moderator
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41 |
For me: near wall modelling and wall function are linked
>>You will use a wall function for modelling effects near the walls *y+ estimation --> http://www.cfd-online.com/Tools/yplus.php *BL in Gambit --> https://www.sharcnet.ca/Software/Gam...tm#mesh_blayer
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In memory of my friend Hervé: CFD engineer & freerider |
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December 23, 2014, 05:22 |
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#3 |
New Member
cecè
Join Date: Dec 2014
Posts: 3
Rep Power: 11 |
Hello max,
first of all thank you for responding to my question . I do not know if I have to use to force the boundary layer or I can also use the MAP algorithm ?? I had divided the domain into four subdomains and using the map I made the mesh . I attach a photo of the mesh that I made so you can give me an opinion . Thank You have a nice day |
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December 23, 2014, 05:29 |
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#4 |
Super Moderator
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41 |
you can work with map, then your BL will be "integrated" within your mesh.
But if you want to adapt your BL, then it will give you some work. If you create the BL, with the tool, then you will adapt it more easily To convince you try to reduce your first cell's height with 50%
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In memory of my friend Hervé: CFD engineer & freerider |
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December 23, 2014, 05:47 |
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#5 |
New Member
cecè
Join Date: Dec 2014
Posts: 3
Rep Power: 11 |
well thanks for the advice ...
Now another question : I have to create the BL only in the region after the sudden expansion or even in the inlet region ?? Looking at the photo of the mesh that I have attached you think it might be a good start for the study ???? If the kind of discretization is ok now I will create the BL where it is appropriate , and follow that road... |
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December 23, 2014, 06:05 |
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#6 |
Super Moderator
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41 |
create the BL on each wall (not at inlet or outlet)
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In memory of my friend Hervé: CFD engineer & freerider |
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