[spalartallmaras]

Hello,

I run simple airfoil simulation with Spalart-Allmaras model, and now I find that there is no information for turbulence length scale after postprocessing.

For example in OpenFoam...

turbulenceFields1
{
    type        turbulenceFields;
    libs        (fieldFunctionObjects);
    
    fields
    ( 
      R 
      L
    );
}

OpenFOAM can calculate the Reynolds stress tensor (R), but no turbulence length scale (L). Should I change the model to calculate turbulence length scale?

[HPE]

With the version you had, unfortunately, calculation of "L" was not possible. Because, the computation of "L" in the "turbulenceFields" function object requires "k" and "epsilon" fields which were not available through "SpalartAllmaras".

With the new v2106 version, however, you should be able to calculate "L" with "SpalartAllmaras" model, because "k" and "epsilon" were made available.

Hope this helps.

[hasanmas]

Hallo,

i have question that is some how related to this thread.

i am trying to compare the same simulation a simulation that I have of airfoil using the k-omega-SST model to the same simulation using Spalart-Allmaras.

The problem i am facing right now is not being able to convert the boundary conditions from one model to there.

sofar i am working with this tool to get the boundary conditions of the k-omega-SST model

http://www.wolfdynamics.com/tools.html


thank you for your help

[faysaal]

Can u plz explain it a little bit more?

[faysaal]

Originally Posted by HPE

With the version you had, unfortunately, calculation of "L" was not possible. Because, the computation of "L" in the "turbulenceFields" function object requires "k" and "epsilon" fields which were not available through "SpalartAllmaras".

With the new v2106 version, however, you should be able to calculate "L" with "SpalartAllmaras" model, because "k" and "epsilon" were made available.

Hope this helps.

can u plz explain a little more?

[LuckyTran]

the turbulenceFields function object was developed for other models and calculates the turbulence length scale from the k and epsilon fields. The Spalart Almaras model isn't a k-epsilon model and so those fields don't exist and they couldn't be computed. Spalart Allmaras is a nutilda model.

Use a newer version of the tool which supports Spalart Allmaras. You need to convert the "turbulence" of other models into an equivalent k and equivalent epsilon field.

[faysaal]

Originally Posted by LuckyTran

the turbulenceFields function object was developed for other models and calculates the turbulence length scale from the k and epsilon fields. The Spalart Almaras model isn't a k-epsilon model and so those fields don't exist and they couldn't be computed. Spalart Allmaras is a nutilda model.

Use a newer version of the tool which supports Spalart Allmaras. You need to convert the "turbulence" of other models into an equivalent k and equivalent epsilon field.

Thanks for the explanation