New VOF multiphaseStabilizedTurbulence fvOption

Summary

Applies corrections to turbulence kinetic energy equation and turbulence viscosity field for incompressible multiphase flow cases.

Turbulence kinetic energy is over-predicted in incompressible VOF solvers at the phase interface and throughout the water column in nearly-potential flow regions beneath surface waves.

This fvOption applies corrections based on the references:

Buoyancy source term in turbulence kinetic energy equation:

    Devolder, B., Rauwoens, P., and Troch, P. (2017).
    Application of a buoyancy-modified k-w SST turbulence model to
    simulate wave run-up around a monopile subjected to regular waves
    using OpenFOAM.
    Coastal Engineering, 125, 81-94.

Correction to turbulence viscosity:

    Larsen, B.E. and Fuhrman, D.R. (2018).
    On the over-production of turbulence beneath surface waves in
    Reynolds-averaged Navier-Stokes models
    J. Fluid Mech, 853, 419-460

Resolved bugs (If applicable)

See #1433 (closed)

Details of new models (If applicable)

The implementation is based on the form for the k-epsilon turbulence model.

Example usage:

multiphaseStabilizedTurbulence1
{
    type            multiphaseStabilizedTurbulence;
    active          yes;

    multiphaseStabilizedTurbulenceCoeffs
    {
        // Optional coefficients
        lambda2         0.1;   // A value of 0 sets the nut correction to 0
        Cmu             0.09;  // from k-epsilon model
        C               1.51;  // model coefficient from k-omega model
        alpha           1.36;  // 1/Prt
    }
}

The model C coefficient for the k-epsilon model equates to C2/C1 = 1.33; the (default) value of 1.51 comes from the k-omega model and is more conservative.

Risks

Modular - low risk

Credits

Thanks go to the Turbulence Technical Committee, and the useful discussions with and code testing by Bjarke Eltard-Larsen and David Fuhrman (Technical University of Denmark).