How to compile a new turbulence model

[Chow2025]

Dear Professor He, we have compiled a new SST model in the latest version of dafoam. However, it was discovered that even if the original SST code was completely copied in the src/adjoint/DAModel directory and the name "kOmegaSST" was changed to another one, the calculation results would be different from those of the built-in SST model. We don't know why this happens. Logically speaking, after registering the names in the newTurbModels folder, all the turbulence model calculations should be completed in the src directory and the calculation results should be exactly the same. But we found that this sometimes leads to significant errors.

[Chow2025]

src/newTurbModels/models/kOmegaSSTtest.C

template<class BasicTurbulenceModel>
tmp<volScalarField> kOmegaSSTtest<BasicTurbulenceModel>::k() const
{
    return this->k_;
}

template<class BasicTurbulenceModel>
tmp<volScalarField> kOmegaSSTtest<BasicTurbulenceModel>::epsilon() const
{

    return this->k_* this->omega_ * scalar(0.09);
}

After a thorough investigation, we discovered that the problem lay in the registration of the variable. If the registration template of the SAFv3 model is directly copied, it will cause significant errors when dealing with the case of using wall functions, but it generally won't cause major errors when dealing with the case of directly analyzing the boundary layer. We solved this problem by registering the variables according to the aforementioned code. It should be noted that if you have registered the turbulence model once before, after making the modifications, you need to run ./Allclean first, and then ./Allmake (in Version 4). Otherwise, the corrected code will not take effect. If you have any better suggestions regarding the code in this area, please feel free to correct us!

[friedenhe]

Thanks very much for this feedback! It is indeed a problematic setting in DAFoam. We will add a note for future developments that the new turbulence model should return proper APIs for wall function!