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 anup November 6, 2007 02:00

turbulence model fr Core annular flow

i hv to simulate core annular flow(thus 2 immisible fluids, one flowing in the core of another) ....i m able to do it without turbulence. thr reynolds no is about 5000. which turbulence model should be the best ?

 k.baker November 6, 2007 02:07

Re: turbulence model fr Core annular flow

try the k-epsilon model and use the VOF model for multiphase flow but you need also check your y+ for best wall treatment method.

K.Baker

 anup November 6, 2007 02:12

Re: turbulence model fr Core annular flow

which k-e model to use?... and i hv used VOF model and how do we check the y+ for best wall treatment?

 k.baker November 6, 2007 02:30

Re: turbulence model fr Core annular flow

the k-elsilon model one of models for turbulence you can use the standard or rng its best for multiphase flow siumlations. choosing wall treatment is important to improve your results near wall and this depend on the value of y+ (see the manual for more information about y+) but you cannot know the value of y+ before starting the simulation after the run is complete (at post-processing) you can draw a line or iso-surface at the wall then go to display contours then select turbulence>Wall Yplus then select the line or iso-surface you draw in the last step hence you will get the contours for Y+. Hence you can decide which the perfect choice for wall treatment as follows: 1) when you see y+<=5 you have to use enhanced wall treatment. 2) if your 30 <y+< 300 you can use either standard WF (wall functions) or non-equlibrium WF.

The second choice is better for multiphse flow.

Hope this be useful

k.baker

 k.baker November 6, 2007 02:32

Re: turbulence model fr Core annular flow

the k-elsilon model one of models for turbulence you can use the standard or rng its best for multiphase flow siumlations. choosing wall treatment is important to improve your results near wall and this depend on the value of y+ (see the manual for mor

 anup November 6, 2007 03:54

Re: turbulence model fr Core annular flow

thnk u a lot ... that was very helpful.. may i know what do u do ?

 anup November 6, 2007 14:58

Re: turbulence model fr Core annular flow

plz help me .. i m not able to simulate core anuular flow .. ( i could only do it if i give the initial boundary condition of the inlet as a core of the fluid itself..otherwise if i give a mixture it forms just bubles n not CAF) ..plz gimme ur mail id

 k.baker November 7, 2007 02:42

Re: turbulence model fr Core annular flow

hi anup unfortunately I work with stratified flow not annular so i cannot help you more sorry. K.Baker

 anup November 7, 2007 03:30

Re: turbulence model fr Core annular flow

can i know abt u and ur occupation?

 k.baker November 7, 2007 03:51

Re: turbulence model fr Core annular flow

How you know my occupation?

 anup November 7, 2007 03:52

Re: turbulence model fr Core annular flow