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

k-epsilon model - k term in the U-equation

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 6, 2011, 10:09
Default k-epsilon model - k term in the U-equation
  #1
New Member
 
Gregory
Join Date: Nov 2010
Location: Dresden
Posts: 14
Rep Power: 6
catapult is on a distinguished road
Hi,

I am having a close look at the k-epsilon model implemented for incompressible flows in Openfoam.

in the following piece of code:
tmp<fvVectorMatrix> kEpsilon::divDevReff(volVectorField& U) const
{
return
(
- fvm::laplacian(nuEff(), U)
- fvc::div(nuEff()*dev(fvc::grad(U)().T()))
);
}

The k term in the Boussinesq eqauation ( 2/3 * k * delta_ij ) does not appear.
Where can I find this term in the implementation?

Thanks for your help!
Gregory
catapult is offline   Reply With Quote

Old   June 6, 2011, 11:11
Default
  #2
Member
 
The True
Join Date: Dec 2010
Posts: 80
Rep Power: 6
Eren10 is on a distinguished road
You can find it in the file kEpsilon.C. I made a copy of it here:

Quote:
tmp<volSymmTensorField> kEpsilon::R() const
00140 {
00141 return tmp<volSymmTensorField>
00142 (
00143 new volSymmTensorField
00144 (
00145 IOobject
00146 (
00147 "R",
00148 runTime_.timeName(),
00149 mesh_,
00150 IOobject::NO_READ,
00151 IOobject::NO_WRITE
00152 ),
00153 ((2.0/3.0)*I)*k_ - nut_*twoSymm(fvc::grad(U_)),
00154 k_.boundaryField().types()
00155 )
00156 );
00157 }

I see that the minus sign is reversed ~? maybe it is multiplied with minus somewhere else !!!!!
Eren10 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
Use of k-epsilon and k-omega Models Jade M Main CFD Forum 12 June 2, 2015 13:16
Herschel-Bulkley non-Newtonian viscosity model has term with sign error pbryant OpenFOAM Bugs 5 June 18, 2013 23:53
Source Term on Scalar Transport Equation - crashing simulation alessio.nz OpenFOAM 19 February 8, 2011 08:38
Hentalpy equation openfoam - miss a term lions85 OpenFOAM 2 August 18, 2010 12:12
Constant velocity of the material Sas CFX 15 July 13, 2010 08:56


All times are GMT -4. The time now is 00:35.