CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   The k-epsilon model (http://www.cfd-online.com/Forums/cfx/20590-k-epsilon-model.html)

Luis August 24, 2004 10:54

The k-epsilon model
 
The linear k-epsilon model assumes that the turbulence viscosity is linked to the turbulence kinetic energy and dissipation via the relation:

μt=Cμ*ρ*k^2/ε

Where Cμ is a constant (k-e Turbulence model constant). However, this linear model is inappropriate for swirl flows. Hence, a Cμ as a function of a shear parameter is usually defined to represent better those type of flows. Therefore, I would like to ask if is a way to define Cμ as a non constant parameter (as a function) using CFX 5.6 or 5.7

Jeff August 25, 2004 23:38

Re: The k-epsilon model
 
You're better off using a Reynolds Stress model which solves the anisotropic Reynolds stresses in swirling flows. Hint: start with k-epsilon, and then restart using the Reynolds Stress model.

Jeff

Luis August 26, 2004 10:59

Re: The k-epsilon model
 
Thank you Jeff, but because I have no computer power right now, I have to use the k-epsilon model until I get a definite model. Any other suggestions that could help me?

Luis

Jeff August 26, 2004 22:12

Re: The k-epsilon model
 
I haven't looked at the CCL for the turbulence models, but C_mu should be a CCL parameter (option). Look in the rules file (under the /etc directory....but don't modify this file!!!) for the k-epsilon section and see if the model constants are parameters. If they are, your can edit your CCL file and set the model constant to a CEL variable. The CEL variable can then be a function of just about anything.

Jeff

Luis August 27, 2004 20:42

Re: The k-epsilon model
 
Thank you Jeff, I will try now

girish August 31, 2004 23:48

Re: The k-epsilon model
 
dear sir,

i want to know details of K-epsilon model,if u sent me the details i will thankful to you

yours faithfully

girish

Luis September 1, 2004 11:10

Re: The k-epsilon model
 
Hi Girish

You can get detail information of the model in the CFX manual under Two equation turbulence model. Also, you can read An introduction to Computational Fluid Dynamics, The Finite Volume Method by H. K. Versteeg, 1995.

Luis


All times are GMT -4. The time now is 18:34.