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-   -   [GAMBIT] evaluting meshing and velocity profile near the wall (http://www.cfd-online.com/Forums/ansys-meshing/71823-evaluting-meshing-velocity-profile-near-wall.html)

zandi January 16, 2010 15:43

evaluting meshing and velocity profile near the wall
 
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

bob12 January 19, 2010 04:57

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.

zandi February 17, 2010 07:51

Quote:

Originally Posted by bob12 (Post 243041)
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

feizaghaee February 18, 2010 16:38

if you'd like to consider the secondary flow K-e is not a good model.


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