[Maoyanjun]

Hello everyone:
I am using the waves2foam to generate Stokes II waves. But when I tried to use the k omega turbulence model or the k epsilon model, I got a significant dissipation of wave height. Is it normal or not? hope for your suggestions!
--------------------------------
the wave condition is as follow:
the length of the wave tank L =50m, the location of the Probes ProbeVOF1=5.0m away from the inlet; ProbeVOF2=10.0m; ProbeVOF3=20.0m; ProbeVOF4=30.0m; ProbeVOF5=49.0m;
the wave height 0.5m；wave period T=2.4s，water depth h=10.0m
------------------------------------------
boundary conditions for k, $\omega$ and nut:
k:
```

internalField   uniform 0.001;

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"
    inlet
    {
        type            zeroGradient;
        //value           uniform 0.001;
       // I have tried the fixedValue boundary, kqRWallFunction, also got similar results
    }

    outlet
    {
        type            zeroGradient;
        //value           uniform 0.001;
        // I have tried the fixedValue boundary, kqRWallFunction, also got similar results
    }

    bottom
    {
        type            kqRWallFunction;
        value           uniform 0.001;
    }

    frontBack
    {
        type           empty;
    }
    atmosphere
    {
        type            inletOutlet;
        inletValue      uniform 0.001;
        value           uniform 0.001;
    }

```

omega:

```

boundaryField
{
    inlet
    {
        type            zeroGradient;
        //value           $internalField;
    }
    outlet
    {
        type            zeroGradient;
        //value           $internalField;
    }
    bottom
    {
        type            omegaWallFunction;
        value           $internalField;
    }

    atmosphere
    {
        type            inletOutlet;
        inletValue      $internalField;
        value           $internalField;
    }
    frontAndBack
    {
        type            empty;
    }
}

```

nut：

```

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"
    inlet
    {
        type            nutkWallFunction;
        Cmu             0.09;
        kappa           0.41;
        E               9.8;
        value           uniform 0;
    }

    outlet
    {
        type            nutkWallFunction;
        Cmu             0.09;
        kappa           0.41;
        E               9.8;
        value           uniform 0;
    }

    bottom
    {
        type            nutkWallFunction;
        Cmu             0.09;
        kappa           0.41;
        E               9.8;
        value           uniform 0;
    }
   frontBack
    {
        type            empty;
    }
    atmosphere
    {
        type            calculated;
        value           uniform 0;
    }

```
___________________________
the surface elevation of this four probes:

[Jekke123456789]

Hello,

Did you find a solution for the problem? I have the same problem?

Kind regards

Jente

[mzzmrt]

Heavy dissipation on free surface is a well known problem on VOF modeling techniques specially with kOmega based turbulence models. As a solution you can find and try stabilized versions of the turbulence models or you can try higher order models such LienCubic kEpsilon.

[Maoyanjun]

Originally Posted by Jekke123456789

Hello,

Did you find a solution for the problem? I have the same problem?

Kind regards

Jente

> On the over-production of turbulence beneath surface waves in Reynolds-averaged Navier–Stokes models
> Application of a buoyancy-modified k-ω SST turbulence model to simulate wave run-up around a monopile subjected to regular waves using OpenFOAM®

these two papers have give an answer to this problem, but I have not tested them, hope for hearing more tests on these modefied turbulence models.

[HosseinB]

I had experienced the same issue with OpenFOAM v1912 for the k-w sst model. The solution was to reduce the initial values of the KTE and omega, and to refine the mesh (smaller cells). This issue is mainly for structure-free regions. This is a known problem for incompressible VOF turbulence modelling and I could get the solution given here (fvOption) to work beyond a very short period of the onset of my simulations (https://www.openfoam.com/releases/op...nd-physics.php).

[irengclenk]

So far, the best solution I can suggest is using the dissipation control as introduced in Larsen, B., & Fuhrman, D. (2018). On the over-production of turbulence beneath surface waves in Reynolds-averaged Navier–Stokes models. Journal of Fluid Mechanics, 853, 419-460. doi:10.1017/jfm.2018.577. The code is avalaible in here: https://github.com/BjarkeEltardLarsen?tab=repositories