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[GAMBIT] evaluting meshing and velocity profile near the wall

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Old   January 16, 2010, 15:43
Default evaluting meshing and velocity profile near the wall
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Fatema Zandi Goharrizi
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Hi
I'm doing a free surface flow CFD modeling project that the velocity and pressure near the bottom (wall boundary) are important parameters. for evaluating the pressure result I have data and after refining mesh I saw that the pressur was not sensitive to it and I reached to a good answer.

but for velocity I do not have any data and just want to reach an answer that not depedent on mesh size.

I use k-epsilon standard in CFX code

so my limitation for y+ is 20 and 100 (CFX help)
  • now i'm reaching to y+ under 20 and still my velocity profile near the boundary changes due to make the meshes smaller. what can I do
please help
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Old   January 19, 2010, 04:57
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hi,
i think that you try to create a boundary layer near the surface. So the mesh near the surface is very small. in gambit there is a specific buttom for this. the parameters that you controll is:
  1. the first layer
  2. the grow parameter
  3. the number of layer that compose your boundary layer
i thinck that in this way you can see the profile of velocity near the wall.
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Old   February 17, 2010, 07:51
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Quote:
Originally Posted by bob12 View Post
hi,

i think that you try to create a boundary layer near the surface. So the mesh near the surface is very small. in gambit there is a specific buttom for this. the parameters that you controll is:
  1. the first layer
  2. the grow parameter
  3. the number of layer that compose your boundary layer
i thinck that in this way you can see the profile of velocity near the wall.

thank you so much
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Old   February 18, 2010, 16:38
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if you'd like to consider the secondary flow K-e is not a good model.
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