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

DSMC Foam - HArd Sphere Model

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

Like Tree2Likes
  • 2 Post By elfuertes

Reply
 
LinkBack Thread Tools Display Modes
Old   June 19, 2013, 15:07
Question DSMC Foam - HArd Sphere Model
  #1
Member
 
sud
Join Date: May 2013
Posts: 65
Rep Power: 4
archeoptyrx is on a distinguished road
Hello ppl,

I am new to OPENFOAM and i learning it through the tutorials .. I wish i could program by myself for different kind of flow problems .

In DSMCFOAM solver tutorials , for wedge15

// Wall Interaction Model
// ~~~~~~~~~~~~~~~~~~~~~~

WallInteractionModel MaxwellianThermal;

// Binary Collision Model
// ~~~~~~~~~~~~~~~~~~~~~~

BinaryCollisionModel LarsenBorgnakkeVariableHardSphere;

LarsenBorgnakkeVariableHardSphereCoeffs
{
Tref 300;
relaxationCollisionNumber 5.0;
}

If i wanted to change this model to Hard sphere model , what should i do ? ,

Also if i wanted to change the wall interaction model , what should i do ?

I understand that i should program the necessary model in the solver folder inside the installation directory ???

It will be great if some one help me out in this ..

Thanks
archeoptyrx is offline   Reply With Quote

Old   June 24, 2013, 04:59
Default
  #2
New Member
 
Join Date: Jun 2013
Posts: 12
Rep Power: 4
elfuertes is on a distinguished road
Hi archeoptyrx !

First of all, you should look at the other submodels that are already implemented for dsmcFoam, they are in the $FOAM_SRC/lagrangian/dsmc/submodels folder.

If one of them suits you, just change the entry in your dmscProperties dictionnary, for instance :

Code:
WallInteractionModel SpecularReflection;
(and add the required options)

If you really need to add a new model, it will be more complicated.
See the following tutorial that can give you a few hints :

http://openfoamwiki.net/index.php/Ho...dary_condition

Good luck on that,
Sylvain
elfuertes is offline   Reply With Quote

Old   July 3, 2013, 16:45
Default
  #3
Member
 
sud
Join Date: May 2013
Posts: 65
Rep Power: 4
archeoptyrx is on a distinguished road
Yes I got it . But how do i find the constants that has to be included with this ? .. eg

Binary collison model LArsonbarognke .......

{
what i should include here ? . How do i find the constants for this model ?
}
Is it same from the G A Bird book ??? Should i happen to give all the constants that is specified for this model in the book ??

Thanks for the help
sud
archeoptyrx is offline   Reply With Quote

Old   July 5, 2013, 03:59
Default
  #4
New Member
 
Join Date: Jun 2013
Posts: 12
Rep Power: 4
elfuertes is on a distinguished road
Hi,

As I said, you should take a look at the submodel's source code located in the folder :

"$FOAM_SRC/lagrangian/dsmc/submodels/"

For instance, for your specific example : if you look at the "LarsenBorgnakkeVariableHardSphere.C" source file, you will notice these lines in the constructor of this class :

Code:
template <class CloudType>
Foam::LarsenBorgnakkeVariableHardSphere<CloudType>::
LarsenBorgnakkeVariableHardSphere
(
    const dictionary& dict,
    CloudType& cloud
)
:
    BinaryCollisionModel<CloudType>(dict, cloud, typeName),
    Tref_(readScalar(this->coeffDict().lookup("Tref"))),
    relaxationCollisionNumber_
    (
        readScalar(this->coeffDict().lookup("relaxationCollisionNumber"))
    )
{}
As you can see, you will need to provide "Tref" and "relaxationCollisionNumber" entries in the coeff dictionary.

I hope it will help, do not hesitate to look inside the source code and/or to run cases and analyse the output errors.

Sylvain
2bias and archeoptyrx like this.
elfuertes 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
Is it possible to model natural convection in a 2D horizontal model in fluent caitoc FLUENT 1 May 5, 2014 13:32
DO radiation model in OPEN FOAM novice OpenFOAM Running, Solving & CFD 0 July 26, 2012 07:37
mesh airfoil NACA0012 anand_30 OpenFOAM Meshing & Mesh Conversion 12 December 12, 2011 05:16
cgnsToFoam problems with "QUAD_4" cells lentschi OpenFOAM Meshing & Mesh Conversion 1 March 9, 2011 05:49
Import gmsh msh to Foam adorean Open Source Meshers: Gmsh, Netgen, CGNS, ... 24 April 27, 2005 08:19


All times are GMT -4. The time now is 14:51.