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-   -   Everything you need to compute DNS in channel vs OF 2.1.0 (http://www.cfd-online.com/Forums/openfoam-solving/101511-everything-you-need-compute-dns-channel-vs-2-1-0-a.html)

levka May 6, 2012 02:39

Everything you need to compute DNS in channel vs OF 2.1.0
 
1 Attachment(s)
Hello everyone.
Here are everything you need to compute DNS in channel vs OF 2.1.
Attached pdf is comparison this solver with DNS data of Kawamura and "Kim and Moin, 1987". Max divergence by mean "u" vs Moin is 2%, vs Kawamura 0%. Also in pdf there is view of full turbulent velocity profile that was taken during average procedure(10,000-30,000).
Following reference is to download zip file:
http://www.sendspace.com/file/xw4myd

Zip contains:
- solver (modified ico_Foam);
- utility to create tangential mesh spacing;
- test case with perturbed initial data;
- computed averaged data+log file;
- manipulation with data Excel file;
- paper Kim and Moin 1987;
- DNS data from paper above;
- DNS data Kawamura;
- master thesis of Steven van Haren"Testing DNS capability of OpenFOAM
and STAR-CCM+";

In case zip is not available i will e-mail it .


Have fun guys!:cool:

Goutam May 7, 2012 11:22

Thanks for your contribution. What about LES for a pipe flow?

alberto May 7, 2012 16:18

You might want to consider to submit this validation study to the Foundation, once they will start accepting code and contributions. It is surely valuable.

levka May 8, 2012 02:40

nice
 
Nice idea! But how to do it ?

alberto May 8, 2012 02:46

There is no defined procedure yet. When I tried to submit some code I used OpenCFD mantis, and they said they are defining the rules for contributors, and will contact me when ready. Maybe you could ask them if they are interested also in validation studies.

ehsan May 23, 2012 14:54

DNS and Airfoil
 
Dear all

Could someone help me in taking a test of DNS over airfoil?

Thanks

levka May 24, 2012 02:02

...
 
Hello ehsan,

I suggest you to download solver solver from the first post and utilize that for your purpose. Just change mesh and BC according to your case, not forget to use initial conditions with perturbations( you can map them from my case to yours using mapField utility). And enjoy. Be in touch. I am interesting in the results.

ehsan May 24, 2012 02:32

Dear Levka

Thanks a lot, we will work on this topic and will be in touch. However, does 2D DNS solution is very time consuming?

Regards
Ehsan

levka May 24, 2012 03:54

...
 
Quote:

Originally Posted by ehsan (Post 362795)
Dear Levka

Thanks a lot, we will work on this topic and will be in touch. However, does 2D DNS solution is very time consuming?

Regards
Ehsan

That depends on your mesh and mesh it self should be defined according to comparison some integral parameter (for example U+ profile or Cf, Cd ) with some closest benchmark problem. Got it?
Cheers

ehsan May 24, 2012 04:58

Dear Levka

In fact, I recently saw this paper:
http://www.sciencedirect.com/science...45793004001203

where the flow simulation over two dimensional and three dimensional airfoil had been reported, in Fig. 7 the U velocity had been reported and we will try to compare our results with this paper.

In fact, I am not familiar with DNS at all while I had worked on LES before, so it took me some time to understand DNS. I downloaded the file you prepared and work on it now.

Regards and thanks
Ehsan

Farshad585 May 26, 2012 15:34

Run b y using dnsFoam
 
Hi everybody
I want to simulate an airfoil and analyze it by dnsFoam. I've used boundary condition as it is in incompressible/simplefoam/2Dairfoil
I've started to run by dnsFoam, but there are the below errors:
--> FOAM FATAL ERROR:
calculated number of cells is incorrect

From function Kmesh::Kmesh(const fvMesh& mesh)
in file Kmesh/Kmesh.C at line 84.

FOAM aborting

#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#1 Foam::error::abort() in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#2 Foam::Kmesh::Kmesh(Foam::fvMesh const&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/librandomProcesses.so"
#3
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/dnsFoam"
#4 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6"
#5
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/dnsFoam"
Aborted


Could anybody help me what should I do?

levka May 28, 2012 10:08

....
 
Hello,Farshad585
that error maybe coursed by either you did not run blockmesh, either your initial field is generated not for your mesh.
Best

Quote:

Originally Posted by Farshad585 (Post 363258)
Hi everybody
I want to simulate an airfoil and analyze it by dnsFoam. I've used boundary condition as it is in incompressible/simplefoam/2Dairfoil
I've started to run by dnsFoam, but there are the below errors:
--> FOAM FATAL ERROR:
calculated number of cells is incorrect

From function Kmesh::Kmesh(const fvMesh& mesh)
in file Kmesh/Kmesh.C at line 84.

FOAM aborting

#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#1 Foam::error::abort() in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#2 Foam::Kmesh::Kmesh(Foam::fvMesh const&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/librandomProcesses.so"
#3
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/dnsFoam"
#4 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6"
#5
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/dnsFoam"
Aborted


Could anybody help me what should I do?


Farshad585 May 28, 2012 18:38

Quote:

Originally Posted by levka (Post 363442)
Hello,Farshad585
that error maybe coursed by either you did not run blockmesh, either your initial field is generated not for your mesh.
Best

Thanks a lot

aerospain November 13, 2012 10:30

Hi levka,

Could you explain how to proceed with the zip file you made available in order to build the ico_DNS and run it, please?

thanks!

Farshad585 December 26, 2012 06:56

least sqaures & fourth order
 
Hi everybody
I've used least squares and fourth order for discretization for pressure gradient (grad(p)), but I don't know the performance of least sqaures and fourth order. Could somebody give me some information about it?
regards

student_07 June 21, 2013 06:07

Hallo Levka,



I have one question to your solver. I'm still a beginner to OpenFoam, so don't wonder, if it is obvious to you.



I ran the test file and it works fine. Now I want to modify it and want to use a constant inlet velocity as boundry condition. In "constant/transportProperties" you set a pressure gradient "gradP". But there is also a "transportProperties_channel" file in which U_bar (probably an average velocity) can be set instead of the pressure gradient.


How do I have to change the solver to use a constant inlet velocity? When I just use Ubar, OpenFoam still requires a pressure gradient?


Regards,


Klaus

Farshad585 June 21, 2013 14:09

Quote:

Originally Posted by student_07 (Post 435242)
Hallo Levka,



I have one question to your solver. I'm still a beginner to OpenFoam, so don't wonder, if it is obvious to you.



I ran the test file and it works fine. Now I want to modify it and want to use a constant inlet velocity as boundry condition. In "constant/transportProperties" you set a pressure gradient "gradP". But there is also a "transportProperties_channel" file in which U_bar (probably an average velocity) can be set instead of the pressure gradient.


How do I have to change the solver to use a constant inlet velocity? When I just use Ubar, OpenFoam still requires a pressure gradient?


Regards,


Klaus

hi
you shoul go to system/fvscheme and set pressure gradient as it show gradP

Farshad585 June 21, 2013 14:10

hi
you shoul go to system/fvscheme and set pressure gradient as it show gradP

levka June 23, 2013 07:16

I suggest you to look at regular channel solver and it's tutorial. "Ubar" is used over there without any gradP.

lixx July 9, 2013 05:18

Nice work!

In the test folder, I can not find the 0/ folder. So you just started from a precursor run or else?

Quote:

Originally Posted by levka (Post 359522)
Hello everyone.
Here are everything you need to compute DNS in channel vs OF 2.1.
Attached pdf is comparison this solver with DNS data of Kawamura and "Kim and Moin, 1987". Max divergence by mean "u" vs Moin is 2%, vs Kawamura 0%. Also in pdf there is view of full turbulent velocity profile that was taken during average procedure(10,000-30,000).
Following reference is to download zip file:
http://www.sendspace.com/file/xw4myd

Zip contains:
- solver (modified ico_Foam);
- utility to create tangential mesh spacing;
- test case with perturbed initial data;
- computed averaged data+log file;
- manipulation with data Excel file;
- paper Kim and Moin 1987;
- DNS data from paper above;
- DNS data Kawamura;
- master thesis of Steven van Haren"Testing DNS capability of OpenFOAM
and STAR-CCM+";

In case zip is not available i will e-mail it .


Have fun guys!:cool:



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