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Old   January 23, 2011, 07:05
Default Turbulence model
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Atiieh Rostami
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Hi Dears
I want to simulate the undular hydraulic jump (hydraulic jump with stationary wave).In first step, I did the model with laminar flow. In next step I want to study the turbulence model in this area.
When I active k-e or RNG model, the simulation is terminated after a minute.
What should I do for the simulation?

Regards
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Old   January 24, 2011, 01:27
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Daniel Valero
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Quote:
Originally Posted by ati_ros61 View Post
Hi Dears
I want to simulate the undular hydraulic jump (hydraulic jump with stationary wave).In first step, I did the model with laminar flow. In next step I want to study the turbulence model in this area.
When I active k-e or RNG model, the simulation is terminated after a minute.
What should I do for the simulation?

Regards
What diagnostic did you get?
May be you are using an implicit model for viscosity. I mean, RNG and k-eps are turbulence models based on a dissipation and a transport equation. In this kind of models (which involve a transport equation), viscous diffusion terms are always aproximated explicitly.

Hope it helps
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Old   January 26, 2011, 00:42
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Atiieh Rostami
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Originally Posted by Davahue View Post
What diagnostic did you get?
May be you are using an implicit model for viscosity. I mean, RNG and k-eps are turbulence models based on a dissipation and a transport equation. In this kind of models (which involve a transport equation), viscous diffusion terms are always aproximated explicitly.

Hope it helps
Dear Davahue
Thank you for reply.
I used explicit model for viscousity when I do with K-e or RNG but I got same result .
I received this message from Flow3D:

============= mentor tip ===============
persistent f-packing location at t= 0.52021E+01
x= 0.99991E+01, y= 0.00000E+00, z=-0.33636E-01
i=5495, j= 2, k= 5
f= 0.96045E+00
recommend reducing cfpk by factor of 10
========================================

I change cfpk to 10 or 20 but the procedure did not change.

Regards
Ati
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Old   January 26, 2011, 02:36
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Daniel Valero
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try with some Vof Lagrangian model and/or no F-Packing at the beginning of the simulation at least
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