# Turbulence model

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 January 23, 2011, 07:05 Turbulence model #1 New Member   Atiieh Rostami Join Date: Oct 2009 Location: malaysia Posts: 14 Rep Power: 9 Sponsored Links 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

January 24, 2011, 01:27
#2
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Daniel Valero
Join Date: Sep 2010
Location: Aachen, Germany
Posts: 42
Rep Power: 8
Quote:
 Originally Posted by ati_ros61 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

January 26, 2011, 00:42
#3
New Member

Atiieh Rostami
Join Date: Oct 2009
Location: malaysia
Posts: 14
Rep Power: 9
Quote:
 Originally Posted by Davahue 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
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

 January 26, 2011, 02:36 #4 Member   Daniel Valero Join Date: Sep 2010 Location: Aachen, Germany Posts: 42 Rep Power: 8 try with some Vof Lagrangian model and/or no F-Packing at the beginning of the simulation at least

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