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-   -   K-episilon viscous model----Constant value. (http://www.cfd-online.com/Forums/fluent/28817-k-episilon-viscous-model-constant-value.html)

Jie August 13, 2001 22:54

K-episilon viscous model----Constant value.
 
If I use K-episilon model, there are two values to set for boudary conditions: Turb. Kinetic Energy and Turb.dissipation Rate. Both of the default values are one ( constant value).

How will they influence the convergence?

Armin Gips August 14, 2001 01:54

Re: K-episilon viscous model----Constant value.
 
I always use the hydraulic diameter. I think it is more easy. Because you can estiamte the diameter from your geometry. And use for heavy turbulence 10 % turbulence intensity.

Armin

Question Man. August 14, 2001 07:28

Re: K-episilon viscous model----Constant value.
 
Hi all,

Yes, I use hydraulic diameter and turbulent intensity, mainly because I know the hydraulic diameter roughly.

Can anyne point me in the direction of papers dealing with boundary condition values for k and epsilon for pumps. I would like to see some typical values. Also, do my INITIAL condition k and epsilon radically effect the solution? I don't think they do (from testing), but I'm wondering if they should...at least in a significant way !! ?? Thanks.

Jie August 16, 2001 11:55

Re: K-episilon viscous model----Constant value.
 
But I use air as the fluid to calculate. And can you tell me haw much the values are?


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