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January 14, 2020, 20:01 
1D Fully Developed Turbulent Pipe flow

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Sharat Chandrasekhar
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Is it possible to obtain meaningful velocity profiles for fully developed pipe flow with onedimensional (radial coordinate only) finite difference simulations using the kepsilon class of turbulence models ?
I know that this can and has been done using mixing length models, but wanted to check with the experts on this forum before embarking on a fool's errand. Thanks 

January 14, 2020, 22:52 

#2  
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Filippo Maria Denaro
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January 15, 2020, 07:53 

#3 
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andy
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Yes. It may not be particularly informative with respect to the velocity profile though because it will simply follow from a linear shear stress. If you know the wall stress from your boundary conditions then the details of the turbulence model becomes irrelevant to the velocity profile.


January 16, 2020, 17:33 

#4 
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It can be done, and I actually suggest it as a useful toy model to learn dealing with turbulence models and/or wall functions.
The same holds, obviously, for other simple settings, like the simpler channel or the boundary layer. The latter however is more interesting because it is the basis for some wall function approaches. However, it depends from what you want to do. Along the same lines, if you extend the approach to the 2D section you can use it as inflow generator (but to be useful you would need it for unstructured 2D grids) 

January 16, 2020, 19:10 

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Sharat Chandrasekhar
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Hello, I'm trying to solve for the complete velocity profile, not just the near wall region, in a concentric annulus.


January 16, 2020, 19:13 

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Sharat Chandrasekhar
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January 16, 2020, 19:14 

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Sharat Chandrasekhar
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January 17, 2020, 07:03 

#8 
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Consider that for the kepsilon family of models you are going to need a wall function, even if in 1D. So, what you will see is how this performs more than how the kepsilon performs. As a matter of fact, most wf models actually mimic the mixing length model, so you might not see any specific difference.
Maybe try the komega family or the SpalartAllmaras. 

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fully developed flow, kepsilon turbulence 
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