CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Pre-Processing

Setting a OpenFoam turbulence case without wall functions

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 9, 2020, 09:36
Exclamation Setting a OpenFoam turbulence case without wall functions
  #1
New Member
 
Lucie Recurt
Join Date: Jun 2020
Posts: 17
Rep Power: 2
lucie.recurt is on a distinguished road
Hello everyone!


I have, for my internship, simulate a turbulent flow in a pipe with a part that make the flow rotating. And I have to test different turbulence models to know which one is the closer to experimental results.



I have read on Internet and thesis that wall functions are not really appropriate for rotating flows that why I don't want to use wall functions.



But I don't understand what to put as boundary condition for the turbulence fields...



Does someone have some clues on how to do that?




Thank you in advance
lucie.recurt is offline   Reply With Quote

Old   September 9, 2020, 22:07
Default
  #2
Member
 
Ardalan
Join Date: Jul 2012
Location: Toronto, Canada
Posts: 72
Rep Power: 10
Ardali is on a distinguished road
Your question is too wide.

Which turbulence model do you want to conduct?
Generally omega, k, epsilon ~ zero, but not zero. LaunderSharma and other low Re models are fine with this setup.

LRR and SSG need another setup.
Ardali is offline   Reply With Quote

Old   September 10, 2020, 03:49
Default
  #3
New Member
 
Lucie Recurt
Join Date: Jun 2020
Posts: 17
Rep Power: 2
lucie.recurt is on a distinguished road
Thank you for your answer.

First I tried with LienCubicKE and the solver simpleFoam. My case is running but the residuals still very high (> 1e-3).Here are my epsilon, k and nut file.
epsilon:

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2006 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object epsilon;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -3 0 0 0 0];

internalField uniform 0.0000037595646871170543;

boundaryField
{
inlet
{
type turbulentMixingLengthDissipationRateInlet;
mixingLength 1;
value uniform 0.7815948027769771;
}
outlet
{
type inletOutlet;
inletValue uniform 0.7815948027769771;

}

"q_wall|cone_wall|e_wall|r_wall|t_wall"
{
type fixedValue;
value uniform 1e-12;
}

}



// ************************************************** *********************** //


k:

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2006 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0.000015915700576801106;

boundaryField
{
inlet
{
type turbulentIntensityKineticEnergyInlet;
intensity 0.016271391811637923;
value uniform 0.016271391811637923;
}
outlet
{
type inletOutlet;
inletValue uniform 0.016271391811637923;
value uniform 0.016271391811637923;
}

"q_wall|cone_wall|e_wall|r_wall|t_wall"
{
type fixedValue;
value uniform 1e-12;
}



}


// ************************************************** *********************** //

nut:

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2006 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -1 0 0 0 0];

internalField uniform 6.063961956727736;

boundaryField
{
inlet
{
type calculated;
value uniform 6.063961956727736;
}
outlet
{
type calculated;
value uniform 6.063961956727736;
}
"q_wall|cone_wall"
{
type calculated;
value uniform 6.063961956727736;
Ks uniform 1.96E-08;
Cs uniform 0.5;
}
r_wall
{
type calculated;
value uniform 26.856840909480123;
Ks uniform 3.13E-06;
Cs uniform 0.5;
}
t_wall
{
type calculated;
value uniform 30.4866884340128;
Ks uniform 1.47E-06;
Cs uniform 0.5;
}
e_wall
{
type calculated;
value uniform 18.782659668926282;
Ks uniform 3.13E-06;
Cs uniform 0.5;
}
}

// ************************************************** *********************** //
lucie.recurt is offline   Reply With Quote

Old   September 10, 2020, 08:21
Default
  #4
Member
 
Ardalan
Join Date: Jul 2012
Location: Toronto, Canada
Posts: 72
Rep Power: 10
Ardali is on a distinguished road
If that is running with the model that you mentioned, cheers.
The BCs are practically correct.
You should keep your yPlus below zero in all time and space.
Ardali is offline   Reply With Quote

Old   December 30, 2020, 15:21
Default
  #5
New Member
 
Josef Dobeš
Join Date: Mar 2012
Location: Czech republic
Posts: 11
Rep Power: 11
Iose is on a distinguished road
Hi lucie.recurt,
can I have question regarding your values for k, epsilon and nut - how did you calculate them? Especially you have different values for internalField and for boundaries.
Thanks
Iose is offline   Reply With Quote

Reply

Tags
boundary, field, openfoam, turbulence, wall functions

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CHT turbulence model wall functions julieng OpenFOAM Running, Solving & CFD 0 February 18, 2019 04:22
Wall Functions & Turbulence Models Query [y plus ranges] TheMightySpartan FLUENT 4 August 18, 2018 02:48
OpenFOAM 4.0 Released CFDFoundation OpenFOAM Announcements from OpenFOAM Foundation 2 October 6, 2017 05:40
abt near wall turbulence wall functions amv Main CFD Forum 0 May 12, 2003 03:38
Wall functions Abhijit Tilak Main CFD Forum 6 February 5, 1999 01:16


All times are GMT -4. The time now is 05:37.