[Wais]

I want to know the meaning of the sigma12/sigma13 in openMixingfoam/constant/transportproperties.

many thx.

[wyldckat]

Greetings Wais,

I'm going to have to ask you a few existential questions:

1. What case are you talking about? I can't find any example case on the Internet named "openMixingfoam".
2. Which OpenFOAM version are you using?

Best regards,
Bruno

[Wais]

Originally Posted by wyldckat

Greetings Wais,

I'm going to have to ask you a few existential questions:

1. What case are you talking about? I can't find any example case on the Internet named "openMixingfoam".
2. Which OpenFOAM version are you using?

Best regards,
Bruno

Sorry,it's interMixingfoam, and I use 2.3.0

[wyldckat]

Ah, OK. I've corrected the thread title.

In the tutorial "multiphase/interMixingFoam/laminar/damBreak" it says this:

Originally Posted by constant/transportProperties

// Surface tension coefficients
sigma12           sigma12 [1 0 -2 0 0 0 0] 0.05;
sigma13           sigma13 [1 0 -2 0 0 0 0] 0.04;

My first guess would be that these were the tension coefficients between X and Y and X and Z... but I'm probably wrong here.

In this file: https://github.com/OpenFOAM/OpenFOAM...ceProperties.H - the description is this:

        //- Surface tension 1-2
        dimensionedScalar sigma12_;

        //- Surface tension 1-3
        dimensionedScalar sigma13_;

On the same file is later on this:

        tmp<volScalarField> sigma() const
        {
            volScalarField limitedAlpha2(max(mixture_.alpha2(), scalar(0)));
            volScalarField limitedAlpha3(max(mixture_.alpha3(), scalar(0)));

            return
                (limitedAlpha2*sigma12_ + limitedAlpha3*sigma13_)
               /(limitedAlpha2 + limitedAlpha3 + SMALL);
        }

Therefore, "sigma12" is for the surface tension between the phase 1 and phase 2, while "sigma13" is for the surface tension between the phase 1 and phase 3.

As to what the surface tension is... it should be be explained in papers and CFD documents related to multiphase

Best regards,
Bruno