[Stefanie.S.W.]

Hello everyone,



in this simulation flow direction is from left to right,

oil is flowing into a water filled tank with baffle walls


In the picture attached you can see that all interfaces are very unstable and "wavy". In real life tests with oil and water the surfaces and interfaces were very calm.



I already got a hint that forces are not well balanced and tried to find optimal settings (see TransportProperties).

Do you have an idea what to change?

Do you think using the SchillerNaumann drag model is causing the behaviour? I tried to implement different drag models but was not able to (simulation did not start, print stack errors...).

Do you have experience with using different drag models with multiphase simulations (all fluids and air present)?
Does the behavior is caused by something else? Maybe fvSchemes, fvSolutions? I will attache them as well.



Thank you a lot for your help!

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

phases
(
     water
     {
         nu         1e-06;
         kappa      1e-06;
         Cp         4195;
         rho        1000;

         diameterModel constant;
         constantCoeffs
         {
             d               1e-3;
         }
     }

     oil //ShellDiala
     {
         nu         9.6e-06;
         kappa      1e-06;
         Cp         4195;
         rho        805;

         diameterModel constant;
         constantCoeffs
         {
             d             1e-4;
         }
     }

     air
     {
         nu         1.48e-05;
         kappa      2.63e-2;
         Cp         1007;
         rho        1;

         diameterModel constant;
         constantCoeffs
         {
             d              3e-3;
         }
     }
     lm//Moussol
     {
         nu         1.5e-05;
         kappa      1e-06;
         Cp         4195;
         rho        1060;

         diameterModel constant;
         constantCoeffs
         {
             d               5e-5;
         }
     }
);

sigmas
(
    (air water)     0.07
    (air oil)       0.03
    (air lm)        0.017

);

interfaceCompression
(
    (air water)     1
    (air oil)       1
    (air lm)        1
    (water oil)     0
    (water lm)      0
    (lm oil)        0
);

virtualMass
(    
   (water oil)     0.4
   (oil water)     0.3
);

drag
(
    (air water)
    {
        type blended;

        air
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        water
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        residualPhaseFraction 1e-3;
        residualSlip 1e-3;
    }

    (air oil)
    {
        type blended;

        air
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        oil
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        residualPhaseFraction 1e-3;
        residualSlip 1e-3;
    }

    (water oil)
    {
        type blended;

        water
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        oil
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        residualPhaseFraction 1e-3;
        residualSlip 1e-3;
    }
    (air lm)
    {
        type blended;

        air
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        lm
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        residualPhaseFraction 1e-3;
        residualSlip 1e-3;
    }

    (lm oil)
    {
        type blended;

        lm
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        oil
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        residualPhaseFraction 1e-3;
        residualSlip 1e-3;
    }
    (lm water)
    {
        type blended;

        lm
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        water
        {
            type SchillerNaumann;
            residualPhaseFraction 0;
            residualSlip 0;
        }

        residualPhaseFraction 1e-3;
        residualSlip 1e-3;
    }

 
);

// This is a dummy to support the Smagorinsky model
transportModel  Newtonian;
nu              nu [ 0 2 -1 0 0 0 0 ] 0;