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-   -   v2f model - periodic boundaries - turbulent viscosity limited to viscosity ratio (http://www.cfd-online.com/Forums/fluent/123482-v2f-model-periodic-boundaries-turbulent-viscosity-limited-viscosity-ratio.html)

 Davide_sd September 13, 2013 10:05

k-omega SST vs V2-f

4 Attachment(s)
Hi all,

i'm trying to compare the performace of k-omega SST vs V2f. I'm simulating an hill.

this is the geometry of the simulation: link

profile at inlet should be such that the flow is in fully developed state. The paper provide me only the velocity profile.
To get the other profiles, i've setup a simulation of a flat terrain with periodic boundary conditions, as explained to me in this thread.

Residuals of the simulation with k-omega SST, for flat terrain (these are good): image
Residuals of the simulation with V2f, for flat terrain (these aren't good): image
As you can see the residuals tend to be periodic... After 350K iterations the periodic-pattern was still the same...

Using the profiles of k, omega,... obtained from simulations above, and the velocity profiles from the paper, i'll get these results: Result of hill simulations

I was expecting the k-omega SST to overstimate the recirculation region; this is the reason i have tryed the V2F. Anyway, i was also expecting the V2F to give better result in respect to k-omega SST; i was wrong...

What can i do to improve the result of V2F?

PS:
1 - all flat terrain simulations have: y+ < 1.
2 - y+ for hill simulations: image
3 - the Reynolds number should be < 4772.

 Davide_sd September 14, 2013 11:53

bump, i've changed the subject of the thread...

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