OpenFoam queries
 

Hi,

I have a few queries with a few openfoam settings:

• northogonalcorrectors :What is the exact function of this keyword?

I read from thes userguide that it has to be between 0 and 60, 0-Hexahedral mesh. I have obtained this from the checkMesh utility
Mesh non-orthogonality Max:61.5 average:12.4196
Does this mean i have to use northogonalcorrectors as 12?

• InternalField : I have successfully implemented the K-omega SST turbulence model for my simulation for inlet and outlet. But, i am not sure how to define the InternalField for the turbulence parameters such as 'k', 'omega' and 'epsilon'.

• Time averaging : I am running a transient simulation and the residuals on my simulation are continiously fluctuating. How can i obtain a time averaged results starting from a certain time step? So, as to check if my computation has converged.

Please enlighten me about these functions.

Thnx 2 everyone in advance!!!;)

varun

p.s: I have a tetrahedral mesh with 10 laminar sub-layers near the wall.

Hi "annoyed"!

I had a look at your profile. 14 posts and all of them of a similar "witty"/unhelpful variety. I think they would be much funnier if you posted them under your real name. Getting an additional anonymous account (and I guess this is your second account) is a bit childish.

If you don't think that these questions are not up to your standards ignore them. It works for most of us

Bernhard

annoyed is just a dump kiddy or frustrated old man, ignore him.

for a clear overview on the meaning and effects of orthogonal correctors refer to Hrvoje's PhD thesis, section 3.7
(available somewhere online ;) )

Hi,

Thank you all for defending me and bearing with my naive questions. I read a lot of threads from the forum and have understood more about orthogonalcorrectors and time averaging of the solution files.

But, i have still not been able to define the Internalfield's for the turbulence parameters. Any help or suggestion of realted threads/topics would be very helpful.


ThanX!!!

varun

Hi vw.cfd,

you can define the internal field by using the following syntax. You have to do that for all of your variables you define in the "0" directory. One hint: Check the value for k which you define in your inlet boundary condition. The value of k has a not negligible influence on the flow downstream even on the flow which is far away from the inlet.
This effect I try to understand right now. Any hints or explanations for this are welcome.

Kind regards
Valle

FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform 0.01;

boundaryField
{
SURF_3
{
type zeroGradient;
}
SURF_2
{
type zeroGradient;
}
SURF_1
{
type zeroGradient;
}
OUTLET
{
type zeroGradient;
}
INLET
{
type fixedValue;
value uniform 50;
}
SURF_3_BACK
{
type zeroGradient;
}
}


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