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-   -   RSM for 2D axisymmetric flows (http://www.cfd-online.com/Forums/fluent/39215-rsm-2d-axisymmetric-flows.html)

Murthy Ravikanti January 12, 2006 09:02

RSM for 2D axisymmetric flows
 
Hi,

I am implementing Reynolds Stress model for 2D axi-symmetric flows without swirl. Hence I am solving only for UU,VV and UV stresses.

I am facing difficulties in getting a physically realistic solution. When I refer to FLUENT's way of solving 2D axisymmetric flows without swirl, I find that it solves WW stress as well!!! ..How is it possible to have finite WW stress when there is no W velocity component in the first place? Thanks, -Murthy

kharicha January 18, 2006 06:12

Re: RSM for 2D axisymmetric flows
 
You forget an important idea: Turbulence is a 3D phenomena.

RSM is a RANS model, which divides the flow into mean flow (U, V, W) and turbulent fluctuations (U*, V*, W*).

You can simulate a 2D axi-symmetric flow with U, V and a mean W equal to 0. BUT THIS DOESN'T MEAN THAT THERE ARE NO FLUCTUATIONS IN THE THETA DIRECTION (WW stress).

SO what you got is realistic.


Murthy Ravikanti January 18, 2006 07:32

Re: RSM for 2D axisymmetric flows
 
Hi Kharicha,

Thanks for providing that insight. It really helps!

-Murthy

Thomas January 25, 2006 12:45

Re: RSM for 2D axisymmetric flows
 
Because turbulence is a 3d phenomen.

thomas


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