SST K- omega turbulence model

mb.pejvak · September 6, 2011, 03:33

Hi
I want to apply SST K- omega turbulence model (menter 1994) in my code. in Omega equation it has one term that called 'cross diffusion term'. I don't know how to discretize this equation. in that paper Menter recommended a linearization but I can't understand it (zonal two equation K-Omega turbulence model for aerodynamic flow, Menter, 1993, formula 27 & 28). Does any one know what should I do?

thanks a lot

Eezyville · September 6, 2011, 11:23

Did you try looking at other resources for clues. Here's a link to NASA's website on turbulence models. http://turbmodels.larc.nasa.gov/sst.html

I hope it can be helpful to you.

mb.pejvak · September 6, 2011, 11:34

Dear Eezyville
thanks for your advice. yes I did. but in that site nothing was said about discritization of cross diffusion term of this model. as I said in the paper of Menter recommended a way but I can't understand it.

swetkyz · September 12, 2011, 16:31

mb.pejvak,

If you are already computing the partial derivatives of k and omega with respect to x_j to solve Eqns. (5) and (6) from Menter 1994, then why not simply multiply them to compute your cross-diffusion term?

Out of curiosity, what is your motivation for implementing the Menter SST model yourself instead of using preexisting software (e.g. openFoam)?

-Zachariah

lalupp · September 13, 2011, 06:18

Check the code freecfd. It is a free c++ code in which cross diffusion term has been implemented. It is in the rans module. Code is not very difficult to understand

mb.pejvak · September 15, 2011, 23:03

Dear Zachariah
I can't understand what you mean. but if you said that I should multiply derivation of k to omega I know that, but I want to descritize it with finite volume and with using of Green law a logarithmic function will be earned and it's impossible to apply this term implicitly.
and about your another question I want apply this turbulence model in self- developing code and It has good answer in laminar flow and I want to use it in turbulent regime.

Mehdi

mb.pejvak · September 15, 2011, 23:08

Dear lalupp
thanks for your helping, but I couldn't find that code you recommended. could you please give me its address or name of site that it is there?

Mehdi

lalupp · September 16, 2011, 01:11

Pls see http://www.freecfd.com/ register and download

swetkyz · September 16, 2011, 09:52

Medhi,

Thank you for clarifying. I had assumed that you were using a finite difference method.

September 6, 2011, 03:33	SST K- omega turbulence model	#1
mb.pejvak Senior Member Mehdi Babamehdi Join Date: Jan 2011 Posts: 158 Rep Power: 15	Hi I want to apply SST K- omega turbulence model (menter 1994) in my code. in Omega equation it has one term that called 'cross diffusion term'. I don't know how to discretize this equation. in that paper Menter recommended a linearization but I can't understand it (zonal two equation K-Omega turbulence model for aerodynamic flow, Menter, 1993, formula 27 & 28). Does any one know what should I do? thanks a lot

September 12, 2011, 16:31		#4
swetkyz Member Zachariah Swetky Join Date: Aug 2011 Posts: 36 Rep Power: 15	mb.pejvak, If you are already computing the partial derivatives of k and omega with respect to x_j to solve Eqns. (5) and (6) from Menter 1994, then why not simply multiply them to compute your cross-diffusion term? Out of curiosity, what is your motivation for implementing the Menter SST model yourself instead of using preexisting software (e.g. openFoam)? -Zachariah Last edited by swetkyz; September 13, 2011 at 09:11. Reason: Clarity

September 13, 2011, 06:18	cross diffusion term	#5
lalupp Member lalupp Join Date: Jul 2010 Location: India Posts: 47 Rep Power: 16	Check the code freecfd. It is a free c++ code in which cross diffusion term has been implemented. It is in the rans module. Code is not very difficult to understand

September 16, 2011, 01:11	Cross diffusion term	#8
lalupp Member lalupp Join Date: Jul 2010 Location: India Posts: 47 Rep Power: 16	Pls see http://www.freecfd.com/ register and download

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September 6, 2011, 11:23		#2
Eezyville New Member Chris Join Date: Oct 2010 Location: Toledo, OH Posts: 24 Rep Power: 16	Did you try looking at other resources for clues. Here's a link to NASA's website on turbulence models. http://turbmodels.larc.nasa.gov/sst.html I hope it can be helpful to you.

September 6, 2011, 11:34		#3
mb.pejvak Senior Member Mehdi Babamehdi Join Date: Jan 2011 Posts: 158 Rep Power: 15	Dear Eezyville thanks for your advice. yes I did. but in that site nothing was said about discritization of cross diffusion term of this model. as I said in the paper of Menter recommended a way but I can't understand it.

September 15, 2011, 23:03		#6
mb.pejvak Senior Member Mehdi Babamehdi Join Date: Jan 2011 Posts: 158 Rep Power: 15	Dear Zachariah I can't understand what you mean. but if you said that I should multiply derivation of k to omega I know that, but I want to descritize it with finite volume and with using of Green law a logarithmic function will be earned and it's impossible to apply this term implicitly. and about your another question I want apply this turbulence model in self- developing code and It has good answer in laminar flow and I want to use it in turbulent regime. Mehdi

September 15, 2011, 23:08		#7
mb.pejvak Senior Member Mehdi Babamehdi Join Date: Jan 2011 Posts: 158 Rep Power: 15	Dear lalupp thanks for your helping, but I couldn't find that code you recommended. could you please give me its address or name of site that it is there? Mehdi

September 16, 2011, 09:52		#9
swetkyz Member Zachariah Swetky Join Date: Aug 2011 Posts: 36 Rep Power: 15	Medhi, Thank you for clarifying. I had assumed that you were using a finite difference method.