second order schemes

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 July 11, 2013, 06:51 #61 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Tussenhausen Posts: 2,708 Blog Entries: 6 Rep Power: 51 Hi all, I made a comparrison of some schemes: https://holzmann-cfd.de/ emjay, Tobias Adam, davibarreira and 1 others like this. Last edited by Tobi; October 28, 2018 at 14:56. Reason: updated link to the correct site, according to post #65

 July 11, 2013, 08:39 #62 Senior Member   Dr. Alexander Vakhrushev Join Date: Mar 2009 Posts: 250 Blog Entries: 1 Rep Power: 19 Great job Tobi! I did something similar for OSCIC'11 conference (see https://docs.google.com/file/d/0BzCp...it?usp=sharing). What I planned to try but still didn't implement it is a mesh dependency of the results: 1. Use unstructured grid 2. Vary an angle of your step profile on structured grid Would be great if some one tests that)))) __________________ Best regards, Dr. Alexander VAKHRUSHEV Christian Doppler Laboratory for "Metallurgical Applications of Magnetohydrodynamics" Simulation and Modelling of Metallurgical Processes Department of Metallurgy University of Leoben http://smmp.unileoben.ac.at

 July 11, 2013, 12:34 #63 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Tussenhausen Posts: 2,708 Blog Entries: 6 Rep Power: 51 Hi, nice hints! If I have time I would do it

August 12, 2013, 13:47
#64
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Join Date: Aug 2012
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Quote:
 Originally Posted by alberto Check your local (cell) Peclet number. The linear scheme requires it to be less than 2 (see Ferziger and Peric for a reference). In your application you might want to use limitedLinear or linearUpwind anyway, which ensure the boundness of the solution. Best,
Dear alberto,
my Pe number is too high, what should i do to reduce it?
what scheme should we use because you said, linear schemes need Pe number lower that 2,
Time = 2000
Calculating Pe
Selecting incompressible transport model Newtonian
Selecting RAS turbulence model SpalartAllmaras
SpalartAllmarasCoeffs
{
sigmaNut 0.66666;
kappa 0.41;
Cb1 0.1355;
Cb2 0.622;
Cw2 0.3;
Cw3 2;
Cv1 7.1;
Cv2 5;
}

Pe max : 309910

End

can you give me some guidance,
Thank you very much.

 July 31, 2014, 07:54 #65 Member   Tobias Adam Join Date: Oct 2013 Location: Siegen Posts: 55 Rep Power: 12 The new website of Tobias Holzmann: http://www.holzmann-cfd.de/index.php...erical-schemes I found it on my research about the different numerical schemes and what they do. Right now I still donīt know how the maths is done by the different numerical schemes. Does anybody have some good papers or links where the interpolation schemes are explained? Best regards Tobi lourencosm likes this.

 July 31, 2014, 08:02 #66 Senior Member   Dr. Alexander Vakhrushev Join Date: Mar 2009 Posts: 250 Blog Entries: 1 Rep Power: 19 Tobi, did you check the reference section of the cfd-online?)))) http://www.cfd-online.com/Wiki/Appro...grids_-_Common for example... Also a PhD thesis of Prof. Jasak has a lot of maths concerning the descretisation. It is also on web. Regards, Alex Tobias Adam and Ramzy1990 like this. __________________ Best regards, Dr. Alexander VAKHRUSHEV Christian Doppler Laboratory for "Metallurgical Applications of Magnetohydrodynamics" Simulation and Modelling of Metallurgical Processes Department of Metallurgy University of Leoben http://smmp.unileoben.ac.at

 October 26, 2014, 11:10 #67 Senior Member   Robert Sawko Join Date: Mar 2009 Posts: 117 Rep Power: 22 Hello everyone, sorry for necrobumping this thread. I was wondering if I could get you interested in my battle against a Delaunay mesh which seems to be very sensitive to fvScheme setup too. I am reporting it here: http://www.cfd-online.com/Forums/ope...tml#post516017 Perhaps you will find it also interesting - getting OpenFOAM to work on this type of meshes would be a significant win for everyone. They can mesh pretty complex geometries although we're test driving it on laminar pipe flow at the moment. We have some successes and some setbacks (paralle runs).

 April 11, 2022, 18:19 #68 Senior Member   qutadah Join Date: Jun 2021 Location: USA Posts: 101 Rep Power: 5 how do i check the local (cell) Peclet number ? Thanks!