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-   -   Comparison of computed velocity profiles with universal profiles (http://www.cfd-online.com/Forums/star-cd/88195-comparison-computed-velocity-profiles-universal-profiles.html)

SMM May 10, 2011 22:21

Comparison of computed velocity profiles with universal profiles
 
Hi All,

Recently I performed simulations of turbulent flow in a pipe using high Reynolds number k-e turbulence model. I used three different grids

1) number of radial cells = 10
2) number of radial cells = 30
3) number of radial cells = 50
while number of axial cells were fixed to 1000 for all cases.

For each one of the above grid the wall adjacent y+ value was kept at 31.5 which is well within the required range for this turbulence model as mentioned by STAR-CD manuals. The issue is that the maximum deviation in the computed velocity profile and the universal profile {i.e. the lograthimic profile u+ = 5.5+2.5*ln(y+)} increases as the number of cells in the radial direction is increased which is unusual kind of a result:confused:.

I would really appreciate if some one can share his or her experience over this issue, if he or she had a chance of encountering this kind of a situation. Another thing is that I have to simulate a two phase flow in a pipe if some one is having any kind of a basic tutorial of two phase flow using STAR-CD kindly share it with me :).


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