[esma]

Hi
I've been trying to use kOmegaSSTSAS in a wind engineering application.
This is actually a great model since this is a hybrid LES-RANS turbulence model that applies RANS kOmegaSST near walls and LES for the rest of the domain where large eddies are of interest in particular in wind engineering.

It appears there are no previous examples provided in the OpenFOAM library and my search through forums didn't end up with any case setup. The thing that puzzled me the most was this turbulence model is subclassed as LES in OpenFOAM (see 1 attached) but when going through the detail description is classified in RAS (see 2). So I struggled at first by setting the model under LES in constant/turbulenceproperties even for a simple model such as a box (see 3) against inlet flow to work. However, when I changed it to RAS it started working and I believe I can see the eddies are formed (see 4). However still in doubt if the settings are correct. Does anyone have experience with such a scaled hybrid model? Should kOmegaSSTSAS be under RAS?. I copy the turbulenceproperties below.


/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2206 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object turbulenceProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

simulationType RAS;

RAS
{
RASModel kOmegaSSTSAS;

turbulence on;

printCoeffs on;

delta vanDriest;


vanDriestCoeffs
{
delta cubeRootVol;
cubeRootVolCoeffs
{
deltaCoeff 1;
}

smoothCoeffs
{
delta cubeRootVol;
cubeRootVolCoeffs
{
deltaCoeff 1;
}

maxDeltaRatio 1.1;
}

Aplus 26;
Cdelta 0.158;
}

}


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

[saeed jamshidi]

If you are going to use kOmegaSSTSAS in the family of Scale Adaptive Simulation (SAS), you should follow as below:

simulationType SAS;

SAS
{

not RAS model.

This is a kind of turbulent model that I found, please check it.

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2112                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      turbulenceProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

simulationType  LES;

LES
{
    LESModel        kOmegaSSTIDDES;
    printCoeffs     yes;
    turbulence      yes;
    delta           IDDESDelta;

    IDDESDeltaCoeffs
    {
        hmax           maxDeltaxyzCubeRoot;
        maxDeltaxyzCubeRootCoeffs
        {
        }
    }
}

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

[esma]

Originally Posted by saeed jamshidi

If you are going to use kOmegaSSTSAS in the family of Scale Adaptive Simulation (SAS), you should follow as below:

simulationType SAS;

SAS
{

not RAS model.

[/CODE]

Thanks, but apparently there is no such thing as "simulationType SAS;" in the turbulent library. It returns the error "Unknown simulation type SAS" followed by "Valid simulationType types: 3(LES RAS laminar).

so it appears the turbulent model types shall be either LES or RAS. I tried the LES as the type with kOmegaSSTSAS model it didn't proceed saying no such model in LES. So I changed it with RAS which appear working.

The IDDES is a detached eddy simulation. Was just wondering about SAS in particular.

Btw, I will try DES as you suggested if still was in doubt about using SAS which looks like it has inherent URANS characteristics rather than LES.

[saeed jamshidi]

Dear esma, you were right!
Please look at: https://www.openfoam.com/documentati...urbulence.html

k-omega-SST SAS is a class of LES model.

[abkahraman]

Hi Esma,


Did it work out for you? I am thinking of trying SAS for my simulations, but there is a lack of information within openfoam framework. Could you share any insights if you have any?


Best Regards,


Ali