CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

[OpenFOAM-2.1.0] kklOmega RAS Turbulence Model (low Re)

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree8Likes

Reply
 
LinkBack Thread Tools Display Modes
Old   June 16, 2014, 09:38
Default
  #61
Senior Member
 
M. Montero
Join Date: Mar 2009
Location: Madrid
Posts: 121
Rep Power: 9
be_inspired is on a distinguished road
Joe ferrari,

In your thesis, you stated that nut at wall should be zeroGradient. I also noticed that internal field is initialized to "zero".

I am having a similar problem like you ( but using SimpleFoam) but I can not solve it changin nut to fixedValue.
kl at the wake of the airfoil is very high and at the end, the solution diverges.
be_inspired is offline   Reply With Quote

Old   July 17, 2014, 04:20
Default
  #62
Member
 
Ye Zhang
Join Date: Dec 2009
Location: Delft,Netherland
Posts: 92
Rep Power: 8
kiddmax is on a distinguished road
Dear Mojtab,

Do you set the omega boundary condition at the wall the same as the komega SST turbulence model? I also made this mistake. Change it to zeroGradient, and should be fine.

Best regards
Ye
kiddmax is offline   Reply With Quote

Old   July 17, 2014, 16:51
Default
  #63
Senior Member
 
Mojtaba.a's Avatar
 
Mojtaba Amiraslanpour
Join Date: Jun 2011
Location: Zanjan, Iran
Posts: 287
Rep Power: 8
Mojtaba.a is on a distinguished road
Send a message via Skype™ to Mojtaba.a
Quote:
Originally Posted by kiddmax View Post
Dear Mojtab,

Do you set the omega boundary condition at the wall the same as the komega SST turbulence model? I also made this mistake. Change it to zeroGradient, and should be fine.

Best regards
Ye
Dear Ye,

Yes, that was the problem.
Thank you for your kind response.

With all the best wishes.
Mojtaba
__________________
Learn OpenFOAM in Persian for free, And ask your questions here.
Complex Heat & Flow Simulation Research Group
If you can't explain it simply, you don't understand it well enough. "Richard Feynman"
Mojtaba.a is offline   Reply With Quote

Old   September 11, 2014, 13:27
Default which airfoil
  #64
New Member
 
Alberto
Join Date: Sep 2013
Posts: 21
Rep Power: 4
malv83 is on a distinguished road
Quote:
Originally Posted by be_inspired View Post
Joe ferrari,

In your thesis, you stated that nut at wall should be zeroGradient. I also noticed that internal field is initialized to "zero".

I am having a similar problem like you ( but using SimpleFoam) but I can not solve it changin nut to fixedValue.
kl at the wake of the airfoil is very high and at the end, the solution diverges.

Hi, I was wondering if you can provide me some more information on the airfoil test case you were running referred in this post. What was the geometry?, Inlet conditions.


Thanks in advanced

Last edited by malv83; September 13, 2014 at 11:09.
malv83 is offline   Reply With Quote

Old   June 17, 2016, 14:39
Default New model
  #65
New Member
 
Alberto
Join Date: Sep 2013
Posts: 21
Rep Power: 4
malv83 is on a distinguished road
After 8 years, there is a new version (or new model) of the k-kl-omega model.

There are a few problems with the k-kl-omega model in the farfield. One of them is the growth of Laminar Kinetic energy when separation occurs. Lopez and Walters have a paper (have not been published yet) correcting this issue:

Maurin Lopez. D. K. Walters. “A recommended correction to the k-kl-omega transition sensitive eddy-viscosity model”. Journal of Fluid Engineering.

This correction has to be made to the 2008 k-kl-omega model from now on.

Now, Lopez and Walters also developed a new transitional model (k-omega-v2) as an alternative to the k-kl-omega one. This new model has more capabilities (it is more reliable) than the k-kl-omega model, especially in the farfield computations. Fortunately the paper for this new model is already publish.

Maurin Lopez. D. K. Walters. “Prediction of transitional and fully turbulent free shear flows using an alternative to the laminar kinetic energy approach”. Journal of Turbulence, Vol 17, Iss. 3, 2016.

If you see the papers, you will immediately see how the k-kl-omega model is not good for free shear flows, and how the new model corrects all those issues. From now on, k-kl-omega users have to start using the new k-omega-v2 model.

Hope this helps
malv83 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Superlinear speedup in OpenFOAM 13 msrinath80 OpenFOAM Running, Solving & CFD 18 March 3, 2015 06:36
Turbulence model for low Reynolds number flow? Nokadu Main CFD Forum 3 May 26, 2013 11:42
Centrifugal Pump and Turbulence Model Michiel CFX 12 January 25, 2010 04:20
turbulence model equation Andy Chen FLOW-3D 4 January 1, 2010 22:45
build your own turbulence model with buoyancy Thomas Baumann OpenFOAM 11 November 23, 2009 09:53


All times are GMT -4. The time now is 14:24.