[shereez234]

Hello Every one;

I have been trying to code the zero equation turbulence model Baldwin - Lomax inorder to replicate some results from a published journal paper. I have been able to remove the k and omega PDE's from a 2 equation turbulence model in order to begin this with.

It works on a principle of calculating two different turbulent viscosity. One for Outer region (Hence nut_Outer) and one for Inner region ( nut_Inner). The two viscosity regions are separated at a wall distance value where the nut_Inner and nut_Outer are equal. nut_Inner is calculated using prandit's van driest formulation and nut_Outer is calculated using a function for wake region and Intermittency factor (Fwake and Fkleb).

The whole model in theory can be found on CFD online wiki:
http://www.cfd-online.com/Wiki/Baldwin-Lomax_model

All the coding went well until I had to define yCrossOver:

    Foam::dimensioned<double> BL::yCrossOver(const volScalarField& NDiff, const volScalarField& nut_Inner) const
    {
        Foam::dimensioned<double> arg = min(y_);
        if (NDiff < ((nut_Inner/nut_Inner)*1e-7))
        {
            return arg;
        }
        else
        {
            return false;
        }

   }

where NDiff is something I have introduced and is the Difference of Nut_Inner and Nut_Outer. I did this just so the division by zero error can be avoided and if not then this becomes a boolean operation which is much harder to code.

Now the question is how I do get the minimum value of y ( walldistance) when nut_Inner is equal to nut_Outer? How do I code this bit?

Sorry about the lengthy post and have a good day!

Thank you.
Shereez

[jherb]

Originally Posted by shereez234

    Foam::dimensioned<double> BL::yCrossOver(const volScalarField& NDiff, const volScalarField& nut_Inner) const
    {
        Foam::dimensioned<double> arg = min(y_);
        if (NDiff < ((nut_Inner/nut_Inner)*1e-7))
        {
            return arg;
        }
        else
        {
            return false;
        }

   }

This looks like you return either a dimensioned double or a boolean, depending on the result of your if statement. This should not work.

Originally Posted by shereez234

Now the question is how I do get the minimum value of y ( walldistance) when nut_Inner is equal to nut_Outer? How do I code this bit?

See https://github.com/OpenFOAM/OpenFOAM...kLOmega.C#L535
and
https://github.com/OpenFOAM/OpenFOAM...kLOmega.H#L203

Here the wall distance is calculated using the OpenFOAM class wallDist.

[shereez234]

How can I code to get the wall distance y_ of a specific cell ( for example maximum vorticity or minimum viscocity) ?