CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Verification & Validation

NASA Turbulence Modeling Resource

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

Like Tree1Likes
  • 1 Post By alexeym

Reply
 
LinkBack Thread Tools Display Modes
Old   May 1, 2015, 17:05
Default NASA Turbulence Modeling Resource
  #1
Senior Member
 
Alexey Matveichev
Join Date: Aug 2011
Location: Nancy, France
Posts: 1,561
Rep Power: 26
alexeym will become famous soon enoughalexeym will become famous soon enough
Dear all,

During preparation of the OpenFOAM validation cases based upon http://turbmodels.larc.nasa.gov, I came across http://turbmodels.larc.nasa.gov/openfoam_issues.html (http://turbmodels.larc.nasa.gov/ChangesToOpenFOAM.pdf).

To be short, OpenFOAM's implementations of SA, SST, and Wilcox models are not quite correct (or "...did not match the equations given on this website").

And my question is: should it be reported as a bug? Was not able to find any discussion on this topic. Or maybe bug report should just contain patch with code corrections?
alexeym is offline   Reply With Quote

Old   May 1, 2015, 18:41
Default
  #2
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 9,801
Blog Entries: 39
Rep Power: 108
wyldckat is a glorious beacon of lightwyldckat is a glorious beacon of lightwyldckat is a glorious beacon of lightwyldckat is a glorious beacon of lightwyldckat is a glorious beacon of lightwyldckat is a glorious beacon of light
Hi Alexey,

I know that sometime ago there was a report about a 6.0 or 60 factor... it's this one: http://www.openfoam.org/mantisbt/view.php?id=1245

And I know there was a fix done a few weeks... er, months ago? Related to f23 or f31... ah, here it is: https://github.com/OpenFOAM/OpenFOAM...7bf8ad06b280ba
But this is odd, because I remember another similar change done more recently... it might have been this: https://github.com/OpenFOAM/OpenFOAM...23b343f30465d4

Either way, there are two details that come to mind:
  1. It's necessary to diagnose which fixes have already been implemented.
  2. It's necessary to validate what these changes affect, if anything at all.
Reporting this as a bug is probably a good idea, at the very least for keeping it on record.
The problem might then be if and how these issues can be fixed or new code can/should be added with these specific implementations.

The other detail that I'm find very strange is that the PDF file does not specify which OpenFOAM version it was tested with...

Best regards,
Bruno
wyldckat is offline   Reply With Quote

Old   May 2, 2015, 03:37
Default
  #3
Senior Member
 
Alexey Matveichev
Join Date: Aug 2011
Location: Nancy, France
Posts: 1,561
Rep Power: 26
alexeym will become famous soon enoughalexeym will become famous soon enough
Hi Bruno,

Thank for the reply. Guess, I should start with verification/validation cases and through comparison of the sources code (let's say 2.3.x branch) and proposed corrections. And after file a bug report.

Quick look at Spalart-Allmaras implementation revealed that the first correction in PDF is already in the code

Code:
tmp<volScalarField> SpalartAllmaras::fv2
(
    const volScalarField& chi,
    const volScalarField& fv1
) const
{
    if (ashfordCorrection_)
    {
        return 1.0/pow3(scalar(1) + chi/Cv2_);
    }
    else
    {
        return 1.0 - chi/(1.0 + chi*fv1);
    }
}
But default value of ashfordCorrection_ is true, so, I think, correction proposed in PDF is usually ignored.
wyldckat likes this.
alexeym 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
Turbulence Modeling meshkati FLUENT 1 October 3, 2016 06:11
Which Turbulence modeling???? Yapoo FLUENT 2 October 2, 2016 02:29
May Focus Area: Turbulence Modeling Jonas Larsson CFD-Wiki 0 May 2, 2006 11:48
Turbulence Modeling RAJURAMAIAH Main CFD Forum 10 August 29, 2004 15:17
turbulence modeling questions llowen Main CFD Forum 3 September 11, 1998 04:24


All times are GMT -4. The time now is 21:49.