[joshmccraney]

Hi All

I am running compressibleInterFoam 6.0 on Ubuntu 18.04. In the constant/thermophysicalProperties.water file looks like:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      thermophysicalProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
/*
thermoType
{
    type            heRhoThermo;
    mixture         pureMixture;
    properties      liquid;
    energy          sensibleInternalEnergy;
}


mixture
{
    H2O;
}


*/
thermoType
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState perfectFluid;
    specie          specie;
    energy          sensibleInternalEnergy;
}

mixture
{
    specie
    {
        molWeight   118.0;	
    }
    equationOfState
    {
        R           3000;		//	J / (kg K)
        rho0        840;		//	DENSITY AT T = 0
    }
    thermodynamics
    {
        Cp          1510;		//	ABOUT 1/3 OF WATER
        Hf          0;			//	
    }
    transport
    {
        mu          0.0017;		// JMC
        Pr          23.;		// JMC K = 0.11
    }
}
// ************************************************************************* //

which is very similar to the depthCharge2D tutorial. The two fluids I am using are air and 2 centistoke silicone oil at room temperature. I am trying to assess what R should be in equationOfState. Since this is not a gas, I'm unsure the value. Here are the units of R, know as the fluid constant. Sure looks like specific heat, but I believe that is specified in thermodynamics under Cp. So I'm confused. Any help is greatly appreciated.

For what it's worth, the perfectFluid seems to follow the equation $\rho = p/(RT) + \rho_0$.